cleaned up

10 files changed, 427 insertions, 296 deletions

diff --git a/src/benchmark.c b/src/benchmark.c
index d3427e4..b6410e3 100644
--- a/src/benchmark.c
+++ b/src/benchmark.c
@@ -1,12 +1,13 @@
 #include "benchmark.h"
 #include "crossbar_generator.h"
+#include "online_crossbar.h"
 #include "read_crossbar.h"
 #include "spires_interface.h"
-#include "online_crossbar.h"
 
 #include <math.h>
 #include <plplot/plplot.h>
 #include <spires.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -21,8 +22,14 @@ int run_online_benchmark(const spires_reservoir_config *config,
 			 double *predictions_out)
 {
 	if (!config || !reservoir || !input_series || num_timesteps == 0 ||
-	    !model_path || !subcircuit_name || !predictions_out)
+	    config->num_neurons == 0 || config->num_inputs == 0 ||
+	    config->num_outputs == 0 || !model_path || !subcircuit_name ||
+	    !predictions_out) {
 		return -1;
+	}
+	if (config->num_neurons > SIZE_MAX / sizeof(double)) {
+		return -1;
+	}
 
 	Online_Crossbar_Config online_config = {
 	    .num_neurons = config->num_neurons,
@@ -39,8 +46,9 @@ int run_online_benchmark(const spires_reservoir_config *config,
 
 	Online_Crossbar *crossbar = NULL;
 	double *state = malloc(config->num_neurons * sizeof(*state));
-	if (!state)
+	if (!state) {
 		return -1;
+	}
 	if (spires_reservoir_reset(reservoir) != SPIRES_OK ||
 	    online_crossbar_init(&online_config, reservoir, &crossbar) != 0 ||
 	    online_crossbar_start(crossbar) != 0) {
@@ -53,15 +61,19 @@ int run_online_benchmark(const spires_reservoir_config *config,
 		const double *input =
 		    input_series + timestep * config->num_inputs;
 		int output_ready = 0;
-		double *previous = timestep == 0
-				       ? NULL
-				       : predictions_out +
-					     (timestep - 1) * config->num_outputs;
+		double *previous =
+		    timestep == 0 ? NULL
+				  : predictions_out +
+					(timestep - 1) * config->num_outputs;
 		if (spires_step(reservoir, input) != SPIRES_OK ||
-		    spires_read_reservoir_state(reservoir, state) != SPIRES_OK ||
+		    spires_read_reservoir_state(reservoir, state) !=
+			SPIRES_OK ||
 		    online_crossbar_submit(crossbar, timestep, state, previous,
 					   &output_ready) != 0 ||
 		    output_ready != (timestep != 0)) {
+			fprintf(stderr,
+				"Online benchmark failed at timestep %zu\n",
+				timestep);
 			free(state);
 			online_crossbar_destroy(crossbar);
 			return -1;
@@ -69,8 +81,8 @@ int run_online_benchmark(const spires_reservoir_config *config,
 	}
 
 	int status = online_crossbar_finish(
-	    crossbar, predictions_out +
-			  (num_timesteps - 1) * config->num_outputs);
+	    crossbar,
+	    predictions_out + (num_timesteps - 1) * config->num_outputs);
 	free(state);
 	online_crossbar_destroy(crossbar);
 	return status;
@@ -81,26 +93,38 @@ int run_benchmark(const spires_reservoir_config *config,
 		  Reservoir_State_Matrix *state_matrix, const char *model_path,
 		  const char *subcircuit_name, double *predictions_out)
 {
-	// copy readout weights and convert to conductances
+	if (!config || !reservoir || !state_matrix || !state_matrix->states ||
+	    state_matrix->num_samples == 0 || state_matrix->num_features == 0 ||
+	    state_matrix->num_features != config->num_neurons ||
+	    config->num_outputs == 0 || !model_path || !subcircuit_name ||
+	    !predictions_out) {
+		return -1;
+	}
+	if (state_matrix->num_samples > SIZE_MAX / state_matrix->num_features ||
+	    state_matrix->num_samples * state_matrix->num_features >
+		SIZE_MAX / sizeof(double)) {
+		return -1;
+	}
+
 	double *initial_resistances = NULL;
+	double *row_voltages = NULL;
+	Crossbar_Output_Matrix crossbar_output = {0};
 	conductance_mapping mapping;
+	int status = -1;
 
 	if (convert_weights_to_resistances(
 		reservoir, config->num_neurons, config->num_outputs, 1000.0,
 		100000.0, &initial_resistances, &mapping) != 0) {
-		return -1;
+		goto cleanup;
 	}
 
-	double *row_voltages =
+	row_voltages =
 	    malloc(state_matrix->num_features * state_matrix->num_samples *
-		   sizeof(double));
+		   sizeof(*row_voltages));
 
-	if (row_voltages == NULL) {
-		fprintf(stderr, "Failed to allocate spikes voltages");
-		free(initial_resistances);
-		free_reservoir_state_matrix(state_matrix);
-		spires_reservoir_destroy(reservoir);
-		return -1;
+	if (!row_voltages) {
+		fprintf(stderr, "Failed to allocate row voltages\n");
+		goto cleanup;
 	}
 
 	for (size_t sample = 0; sample < state_matrix->num_samples; sample++) {
@@ -125,60 +149,49 @@ int run_benchmark(const spires_reservoir_config *config,
 	    .subcircuit_name = subcircuit_name,
 	    .time_step = 1e-6,
 	    .stop_time = state_matrix->num_samples * 1e-6,
-	    .print_state_nodes = 0}; // state nodes is not acutally implemented
+	    .print_state_nodes = 0};
 
 	if (generate_crossbar("output/crossbar.cir", &crossbar_config) < 0) {
-		fprintf(stderr, "failed to create crossbar config");
-		free(initial_resistances);
-		return -1;
+		fprintf(stderr, "Failed to generate crossbar netlist\n");
+		goto cleanup;
 	}
-	printf("Generated crossbar!!");
 
-	// call ngspice for crossbar
 	if (run_ngspice("output/crossbar.cir") < 0) {
-		fprintf(stderr, "Failed to run_ngspice");
-		free(initial_resistances);
-		return -1;
+		fprintf(stderr, "Failed to run ngspice\n");
+		goto cleanup;
 	}
-	printf("ran ngspice!!");
-
-	// crossbar parameters needed for reading
-	Crossbar_Output_Matrix crossbar_output = {
-	    // .num_samples = state_matrix->num_samples,
-	    // .num_outputs = config->num_outputs * 2,
-	    .time = NULL,
-	    .voltages = NULL};
 
 	if (read_crossbar("output/crossbar_output.dat", config->num_outputs * 2,
 			  &crossbar_output) < 0) {
-		fprintf(stderr, "Failed to read crossbar output file");
-		free(initial_resistances);
-		free_crossbar_output_matrix(&crossbar_output);
-		return -1;
+		fprintf(stderr, "Failed to read crossbar output\n");
+		goto cleanup;
 	}
-	printf("read the crossbar outputs!!\n");
 
 	if (convert_output_to_software(
 		config->num_neurons, config->num_outputs,
 		state_matrix->num_samples, crossbar_output.voltages,
 		initial_resistances, crossbar_config.load_resistance, &mapping,
 		row_voltages, SPIKE_AMPLITUDE, predictions_out) < 0) {
-		fprintf(stderr,
-			"Failed to convert crossbar outputs back to software");
-		return -1;
+		fprintf(stderr, "Failed to decode crossbar output\n");
+		goto cleanup;
 	}
 
-	printf("YAY IT WORKED!!! Cleaning up :)\n");
+	status = 0;
+
+cleanup:
 	free(initial_resistances);
 	free(row_voltages);
 	free_crossbar_output_matrix(&crossbar_output);
-
-	return 0;
+	return status;
 }
 
 double calculate_MSE(const double *expected, const double *predicted,
 		     const size_t num_steps, const size_t num_outputs)
 {
+	if (!expected || !predicted || num_steps == 0 || num_outputs == 0) {
+		return NAN;
+	}
+
 	double aggregate = 0.0;
 	for (size_t output = 0; output < num_outputs; output++) {
 		for (size_t timestep = 0; timestep < num_steps; timestep++) {
@@ -197,15 +210,11 @@ double calculate_MSE(const double *expected, const double *predicted,
 int plot_raster(const Reservoir_State_Matrix *matrix,
 		const size_t neurons_to_plot, const double spike_threshold)
 {
-	if (!matrix || !matrix->states || matrix->num_samples == 0) {
+	if (!matrix || !matrix->states || matrix->num_samples == 0 ||
+	    matrix->num_features == 0 || neurons_to_plot == 0 ||
+	    neurons_to_plot > matrix->num_features) {
 		return -1;
 	}
-
-	// if (neurons_to_plot > matrix->num_features) {
-	// 	neurons_to_plot = matrix->num_features;
-	// }
-
-	// count spikes
 	size_t spike_count = 0;
 	for (size_t t = 0; t < matrix->num_samples; t++) {
 		for (size_t n = 0; n < neurons_to_plot; n++) {
@@ -231,7 +240,6 @@ int plot_raster(const Reservoir_State_Matrix *matrix,
 		return -1;
 	}
 
-	// fill spike coordinates
 	size_t k = 0;
 	for (size_t t = 0; t < matrix->num_samples; t++) {
 		for (size_t n = 0; n < neurons_to_plot; n++) {
@@ -293,9 +301,10 @@ int plot_reservoir_predictions(const double *expected, const double *predicted,
 	PLFLT y_min;
 	PLFLT y_max;
 
-	if (!expected || !predicted || num_samples == 0 ||
-	    output_to_plot >= num_outputs)
+	if (!expected || !predicted || !model_path || num_samples == 0 ||
+	    num_outputs == 0 || output_to_plot >= num_outputs) {
 		return -1;
+	}
 
 	x = malloc(num_samples * sizeof(*x));
 	y_expected = malloc(num_samples * sizeof(*y_expected));
@@ -320,17 +329,21 @@ int plot_reservoir_predictions(const double *expected, const double *predicted,
 		y_expected[sample] = (PLFLT)expected[index];
 		y_predicted[sample] = (PLFLT)predicted[index];
 
-		if (y_expected[sample] < y_min)
+		if (y_expected[sample] < y_min) {
 			y_min = y_expected[sample];
+		}
 
-		if (y_expected[sample] > y_max)
+		if (y_expected[sample] > y_max) {
 			y_max = y_expected[sample];
+		}
 
-		if (y_predicted[sample] < y_min)
+		if (y_predicted[sample] < y_min) {
 			y_min = y_predicted[sample];
+		}
 
-		if (y_predicted[sample] > y_max)
+		if (y_predicted[sample] > y_max) {
 			y_max = y_predicted[sample];
+		}
 	}
 
 	{
@@ -338,8 +351,9 @@ int plot_reservoir_predictions(const double *expected, const double *predicted,
 
 		margin = (y_max - y_min) * 0.1;
 
-		if (margin == 0.0)
+		if (margin == 0.0) {
 			margin = 1.0;
+		}
 
 		y_min -= margin;
 		y_max += margin;
@@ -347,8 +361,6 @@ int plot_reservoir_predictions(const double *expected, const double *predicted,
 
 	plsdev("svg");
 
-	// parses real model name
-	// written by chatGPT
 	char filename[256];
 	char model_name[128];
 	const char *base;
@@ -361,8 +373,9 @@ int plot_reservoir_predictions(const double *expected, const double *predicted,
 	dot = strrchr(base, '.');
 	len = dot ? (size_t)(dot - base) : strlen(base);
 
-	if (len >= sizeof(model_name))
+	if (len >= sizeof(model_name)) {
 		len = sizeof(model_name) - 1;
+	}
 
 	memcpy(model_name, base, len);
 	model_name[len] = '\0';
@@ -371,6 +384,9 @@ int plot_reservoir_predictions(const double *expected, const double *predicted,
 		     "output/reservoir_prediction_%s.svg",
 		     model_name) >= (int)sizeof(filename)) {
 		fprintf(stderr, "Output filename is too long\n");
+		free(x);
+		free(y_expected);
+		free(y_predicted);
 		return -1;
 	}
 
@@ -433,8 +449,9 @@ int plot_model_delta(const double *fixed, const double *model,
 	size_t len;
 
 	if (!fixed || !model || !model_path || num_samples == 0 ||
-	    output_to_plot >= num_outputs)
+	    num_outputs == 0 || output_to_plot >= num_outputs) {
 		return -1;
+	}
 
 	x = malloc(num_samples * sizeof(*x));
 	delta = malloc(num_samples * sizeof(*delta));
@@ -453,14 +470,16 @@ int plot_model_delta(const double *fixed, const double *model,
 
 		x[sample] = (PLFLT)sample;
 		delta[sample] = (PLFLT)fabs(model[index] - fixed[index]);
-		abs_delta = (PLFLT)fabs(delta[sample]);
+		abs_delta = delta[sample];
 
-		if (abs_delta > max_abs_delta)
+		if (abs_delta > max_abs_delta) {
 			max_abs_delta = abs_delta;
+		}
 	}
 
-	if (max_abs_delta == 0.0)
+	if (max_abs_delta == 0.0) {
 		max_abs_delta = 1.0e-6;
+	}
 
 	max_abs_delta *= 1.1;
 
@@ -470,8 +489,9 @@ int plot_model_delta(const double *fixed, const double *model,
 	dot = strrchr(base, '.');
 	len = dot ? (size_t)(dot - base) : strlen(base);
 
-	if (len >= sizeof(model_name))
+	if (len >= sizeof(model_name)) {
 		len = sizeof(model_name) - 1;
+	}
 
 	memcpy(model_name, base, len);
 	model_name[len] = '\0';
diff --git a/src/benchmark.h b/src/benchmark.h
index c7ffab6..8c37a9e 100644
--- a/src/benchmark.h
+++ b/src/benchmark.h
@@ -1,8 +1,6 @@
 #ifndef BENCHMARK_H
 #define BENCHMARK_H
 
-#include "crossbar_generator.h"
-#include "read_crossbar.h"
 #include "spires_interface.h"
 #include <stddef.h>
 
diff --git a/src/crossbar_generator.c b/src/crossbar_generator.c
index 4bf6746..2633230 100644
--- a/src/crossbar_generator.c
+++ b/src/crossbar_generator.c
@@ -3,47 +3,19 @@
 
 static int validate_config(const Crossbar_Config *config)
 {
-	printf("validating configs...\n");
-	if (config == NULL) {
-		return -1;
-	}
-	if (config->rows == 0) {
-		return -1;
-	}
-	if (config->columns == 0) {
-		return -1;
-	}
-	if (config->input_series == NULL) {
-		return -1;
-	}
-	if (config->num_samples == 0) {
-		return -1;
-	}
-	if (config->initial_resistance == NULL) {
-		return -1;
-	}
-	if (config->model_path == NULL) {
-		return -1;
-	}
-	if (config->subcircuit_name == NULL) {
-		return -1;
-	}
-	if (config->load_resistance <= 0.0) {
-		return -1;
-	}
-	if (config->time_step <= 0.0) {
-		return -1;
-	}
-	if (config->stop_time <= 0.0) {
-		return -1;
-	}
-	if (config->print_state_nodes != 0 && config->print_state_nodes != 1) {
+	if (!config || config->rows == 0 || config->columns == 0 ||
+	    !config->input_series || config->num_samples == 0 ||
+	    !config->initial_resistance || !config->model_path ||
+	    !config->subcircuit_name || config->load_resistance <= 0.0 ||
+	    config->time_step <= 0.0 || config->stop_time <= 0.0 ||
+	    (config->print_state_nodes != 0 &&
+	     config->print_state_nodes != 1)) {
 		return -1;
 	}
+
 	return 0;
 }
 
-// thus starts fprintf hell...
 static int write_header(FILE *file, const Crossbar_Config *config)
 {
 	if (fprintf(file,
@@ -51,13 +23,12 @@ static int write_header(FILE *file, const Crossbar_Config *config)
 		    "*Rows: %zu\n"
 		    "*Columns: %zu\n",
 		    config->rows, config->columns) < 0) {
-		fprintf(stderr, "Failed to write header at crossbar size");
+		fprintf(stderr, "Failed to write crossbar header\n");
 		return -1;
 	}
 
-	// include the memristor model
 	if (fprintf(file, "\n.include \"%s\"\n", config->model_path) < 0) {
-		fprintf(stderr, "Faile to write header at .include memristor");
+		fprintf(stderr, "Failed to write model include\n");
 		return -1;
 	}
 
@@ -66,35 +37,42 @@ static int write_header(FILE *file, const Crossbar_Config *config)
 
 static int write_input_series(FILE *file, const Crossbar_Config *config)
 {
-	fprintf(file, "\n* SPIRES reservoir states\n");
+	if (fprintf(file, "\n* SPIRES reservoir states\n") < 0) {
+		return -1;
+	}
 
 	for (size_t row = 0; row < config->rows; row++) {
-		fprintf(file, "VROW%zu row%zu 0 PWL(", row, row);
+		if (fprintf(file, "VROW%zu row%zu 0 PWL(", row, row) < 0) {
+			return -1;
+		}
 
 		for (size_t sample = 0; sample < config->num_samples;
 		     sample++) {
 			double time = sample * config->time_step;
-			double state =
+			double voltage =
 			    config->input_series[sample * config->rows + row];
-
-			double voltage = state;
-
-			fprintf(file, "%.17g %.17g ", time, voltage);
+			if (fprintf(file, "%.17g %.17g ", time, voltage) < 0) {
+				return -1;
+			}
+		}
+		if (fprintf(file, ")\n") < 0) {
+			return -1;
 		}
-		fprintf(file, ")\n");
 	}
-	return ferror(file) ? -1 : 0;
+	return 0;
 }
 
 static int write_external_inputs(FILE *file, const Crossbar_Config *config)
 {
-	if (fprintf(file, "\n* Online SPIRES reservoir states\n") < 0)
+	if (fprintf(file, "\n* Online SPIRES reservoir states\n") < 0) {
 		return -1;
+	}
 
 	for (size_t row = 0; row < config->rows; row++) {
 		if (fprintf(file, "VROW%zu row%zu 0 dc 0 external\n", row,
-			    row) < 0)
+			    row) < 0) {
 			return -1;
+		}
 	}
 	return 0;
 }
@@ -102,14 +80,12 @@ static int write_external_inputs(FILE *file, const Crossbar_Config *config)
 static int write_memristor_array(FILE *file, const Crossbar_Config *config)
 {
 	if (fprintf(file, "\n* Memristor Array\n") < 0) {
-		fprintf(stderr,
-			"Failed to write memristor array comment label thing");
+		fprintf(stderr, "Failed to write memristor array header\n");
 		return -1;
 	}
 
 	for (size_t row = 0; row < config->rows; row++) {
 		for (size_t column = 0; column < config->columns; column++) {
-			// initial_resistance here is done wrong, need to fix
 			if (fprintf(file,
 				    "X%zu%zu row%zu col%zu %s"
 				    " PARAMS: Rinit=%.12g\n",
@@ -118,7 +94,7 @@ static int write_memristor_array(FILE *file, const Crossbar_Config *config)
 				    config->initial_resistance
 					[row * config->columns + column]) < 0) {
 				fprintf(stderr,
-					"Failed to write memristor array");
+					"Failed to write memristor array\n");
 				return -1;
 			}
 		}
@@ -129,14 +105,14 @@ static int write_memristor_array(FILE *file, const Crossbar_Config *config)
 static int write_column_loads(FILE *file, const Crossbar_Config *config)
 {
 	if (fprintf(file, "\n* Column Loads\n") < 0) {
-		fprintf(stderr,
-			"Failed to write column loads comment label thing");
+		fprintf(stderr, "Failed to write column-load header\n");
+		return -1;
 	}
 
 	for (size_t column = 0; column < config->columns; column++) {
 		if (fprintf(file, "RLOAD%zu col%zu 0 %.0f\n", column, column,
 			    config->load_resistance) < 0) {
-			fprintf(stderr, "Failed to write column loads");
+			fprintf(stderr, "Failed to write column loads\n");
 			return -1;
 		}
 	}
@@ -146,37 +122,44 @@ static int write_column_loads(FILE *file, const Crossbar_Config *config)
 static int write_simulation(FILE *file, const Crossbar_Config *config)
 {
 	if (fprintf(file, "\n* Simulation\n") < 0) {
-		fprintf(stderr, "Failed to write simulation header");
+		fprintf(stderr, "Failed to write simulation header\n");
 		return -1;
 	}
 
 	if (fprintf(file, ".tran %.17g %.17g uic\n.control\nrun\n",
 		    config->time_step, config->stop_time) < 0) {
-		fprintf(stderr, "Failed to write simulation command");
+		fprintf(stderr, "Failed to write simulation command\n");
 		return -1;
 	}
 	return 0;
 }
 
-static int write_save_date(FILE *file, const Crossbar_Config *config)
+static int write_save_data(FILE *file, const Crossbar_Config *config)
 {
-	fprintf(file, "linearize");
-	for (int column = 0; column < config->columns; column++) {
+	if (fprintf(file, "linearize") < 0) {
+		return -1;
+	}
+	for (size_t column = 0; column < config->columns; column++) {
 		if (fprintf(file, " v(col%zu)", column) < 0) {
-			fprintf(stderr, "Failed to write linearize statements");
+			fprintf(stderr,
+				"Failed to write linearize statement\n");
 			return -1;
 		}
 	}
 
-	fprintf(file, "\nwrdata output/crossbar_output.dat");
-	for (int column = 0; column < config->columns; column++) {
-		fprintf(file, " v(col%zu)",
-			column); // ive given up on error checking
-				 // Im doing too much of it
+	if (fprintf(file, "\nwrdata output/crossbar_output.dat") < 0) {
+		return -1;
+	}
+	for (size_t column = 0; column < config->columns; column++) {
+		if (fprintf(file, " v(col%zu)", column) < 0) {
+			fprintf(stderr,
+				"Failed to write output-data statement\n");
+			return -1;
+		}
 	}
 
 	if (fprintf(file, "\n.endc\n.end") < 0) {
-		fprintf(stderr, "Failed to write end statements");
+		fprintf(stderr, "Failed to write closing statements\n");
 		return -1;
 	}
 	return 0;
@@ -185,15 +168,15 @@ static int write_save_date(FILE *file, const Crossbar_Config *config)
 int generate_crossbar(const char *output_filename,
 		      const Crossbar_Config *config)
 {
-	if (validate_config(config) < 0) {
-		fprintf(stderr, "invalid config");
+	if (!output_filename || validate_config(config) < 0) {
+		fprintf(stderr, "Invalid crossbar configuration\n");
 		return -1;
 	}
 
 	FILE *file = fopen(output_filename, "w");
 
 	if (file == NULL) {
-		fprintf(stderr, "could not create file");
+		fprintf(stderr, "Could not create crossbar netlist\n");
 		return -1;
 	}
 
@@ -202,14 +185,14 @@ int generate_crossbar(const char *output_filename,
 	    write_memristor_array(file, config) != 0 ||
 	    write_column_loads(file, config) != 0 ||
 	    write_simulation(file, config) != 0 ||
-	    write_save_date(file, config) != 0) {
+	    write_save_data(file, config) != 0) {
 
 		fclose(file);
 		return -1;
 	}
 
 	if (fclose(file) != 0) {
-		fprintf(stderr, "failed to close output file");
+		fprintf(stderr, "Failed to close crossbar netlist\n");
 		return -1;
 	}
 	return 0;
@@ -218,14 +201,14 @@ int generate_crossbar(const char *output_filename,
 int generate_online_crossbar(const char *output_filename,
 			     const Crossbar_Config *config)
 {
-	if (validate_config(config) < 0) {
-		fprintf(stderr, "invalid config");
+	if (!output_filename || validate_config(config) < 0) {
+		fprintf(stderr, "Invalid online crossbar configuration\n");
 		return -1;
 	}
 
 	FILE *file = fopen(output_filename, "w");
 	if (file == NULL) {
-		fprintf(stderr, "could not create online crossbar file");
+		fprintf(stderr, "Could not create online crossbar netlist\n");
 		return -1;
 	}
 
@@ -247,7 +230,8 @@ int generate_online_crossbar(const char *output_filename,
 		}
 	}
 
-	if (fprintf(file, "\n.end\n") < 0 || fclose(file) != 0)
+	if (fprintf(file, "\n.end\n") < 0 || fclose(file) != 0) {
 		return -1;
+	}
 	return 0;
 }
diff --git a/src/crossbar_generator.h b/src/crossbar_generator.h
index 8fc754b..b76179b 100644
--- a/src/crossbar_generator.h
+++ b/src/crossbar_generator.h
@@ -4,33 +4,38 @@
 #include <stddef.h>
 
 typedef struct {
-	size_t rows;	// number of neurons
-	size_t columns; // number of outputs
+	/* Physical crossbar dimensions. */
+	size_t rows;
+	size_t columns;
 
-	// array of row input voltages.
-	// length must equal rows (# of rows)
+	/*
+	 * Flat row-major input voltages. Offline generation reads
+	 * input_series[sample * rows + row] for num_samples samples. Online
+	 * generation uses external voltage sources and does not read the values.
+	 */
 	const double *input_series;
 	size_t num_samples;
 
-	// array of initial resistances
-	// stored in row-major order
-	// size must be rows * colums
+	/*
+	 * Flat row-major initial resistances with rows * columns elements:
+	 * initial_resistance[row * columns + column].
+	 */
 	const double *initial_resistance;
 
-	// path to the memory component path
+	/* Path to the SPICE model included by the generated netlist. */
 	const char *model_path;
 
-	// name of subcircuit(specific model)
+	/* Name of the model's SPICE subcircuit. */
 	const char *subcircuit_name;
 
-	// resistance from each column to ground
+	/* Resistance from each physical column to ground. */
 	double load_resistance;
 
-	// transient sim settings
+	/* Transient-analysis sample interval and stop time. */
 	double time_step;
 	double stop_time;
 
-	// 1 = true | 0 = false
+	/* Reserved for state-node output; currently must be 0 or 1. */
 	int print_state_nodes;
 } Crossbar_Config;
 
diff --git a/src/online_crossbar.c b/src/online_crossbar.c
index b01ea19..ff346bd 100644
--- a/src/online_crossbar.c
+++ b/src/online_crossbar.c
@@ -8,6 +8,7 @@
 #include <ngspice/sharedspice.h>
 #include <pthread.h>
 #include <stdbool.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -32,14 +33,41 @@ struct Online_Crossbar {
 	pthread_cond_t progress;
 };
 
+static int config_is_valid(const Online_Crossbar_Config *config)
+{
+	if (!config || config->num_neurons == 0 || config->num_outputs == 0 ||
+	    config->num_timesteps == 0 || !isfinite(config->time_step) ||
+	    config->time_step <= 0.0 || !isfinite(config->spike_amplitude) ||
+	    config->spike_amplitude == 0.0 ||
+	    !isfinite(config->load_resistance) ||
+	    config->load_resistance <= 0.0 || !isfinite(config->r_on) ||
+	    !isfinite(config->r_off) || config->r_on <= 0.0 ||
+	    config->r_off <= config->r_on || !config->model_path ||
+	    !config->subcircuit_name || !config->netlist_path) {
+		return 0;
+	}
+
+	if (config->num_outputs > SIZE_MAX / 2 ||
+	    config->num_neurons > SIZE_MAX / 2 ||
+	    config->num_timesteps > SIZE_MAX / config->num_outputs ||
+	    config->num_timesteps * config->num_outputs >
+		SIZE_MAX / sizeof(double)) {
+		return 0;
+	}
+
+	double stop_time = config->num_timesteps * config->time_step;
+	return isfinite(stop_time) && stop_time > 0.0;
+}
+
 static int callback_text(char *text, int ident, void *user_data)
 {
 	(void)ident;
 	(void)user_data;
 	if (text &&
 	    (strncmp(text, "stderr", 6) == 0 || strstr(text, "Error") != NULL ||
-	     strstr(text, "error") != NULL))
+	     strstr(text, "error") != NULL)) {
 		fprintf(stderr, "ngspice: %s\n", text);
+	}
 	return 0;
 }
 
@@ -77,12 +105,14 @@ static int callback_background(NG_BOOL running, int ident, void *user_data)
 	(void)ident;
 	Online_Crossbar *crossbar = user_data;
 	/* libngspice passes false at worker start and true at worker exit. */
-	if (!running)
+	if (!running) {
 		return 0;
+	}
 	pthread_mutex_lock(&crossbar->mutex);
 	crossbar->simulation_done = 1;
-	if (crossbar->result_count < crossbar->config.num_timesteps)
+	if (crossbar->result_count < crossbar->config.num_timesteps) {
 		fail_locked(crossbar);
+	}
 	pthread_cond_broadcast(&crossbar->progress);
 	pthread_cond_broadcast(&crossbar->state_available);
 	pthread_mutex_unlock(&crossbar->mutex);
@@ -92,28 +122,33 @@ static int callback_background(NG_BOOL running, int ident, void *user_data)
 static int row_from_name(const char *name, size_t *row_out)
 {
 	const char *digits = name + strlen(name);
-	while (digits > name && isdigit((unsigned char)digits[-1]))
+	while (digits > name && isdigit((unsigned char)digits[-1])) {
 		digits--;
-	if (*digits == '\0')
+	}
+	if (*digits == '\0') {
 		return -1;
+	}
 	char *end = NULL;
 	unsigned long value = strtoul(digits, &end, 10);
-	if (end == digits || *end != '\0')
+	if (end == digits || *end != '\0') {
 		return -1;
+	}
 	*row_out = (size_t)value;
 	return 0;
 }
 
 static size_t timestep_for_time(const Online_Crossbar *crossbar, double time)
 {
-	if (time <= 0.0)
+	if (time <= 0.0) {
 		return 0;
+	}
 	double scaled = time / crossbar->config.time_step;
 	/* Hold state[t] over the full interval (t*dt, (t+1)*dt]. */
 	double interval = ceil(scaled - 1.0e-9);
 	size_t timestep = interval <= 1.0 ? 0 : (size_t)interval - 1;
-	if (timestep >= crossbar->config.num_timesteps)
+	if (timestep >= crossbar->config.num_timesteps) {
 		timestep = crossbar->config.num_timesteps - 1;
+	}
 	return timestep;
 }
 
@@ -132,8 +167,9 @@ static int callback_voltage(double *voltage, double time, char *name, int ident,
 
 	size_t timestep = timestep_for_time(crossbar, time);
 	pthread_mutex_lock(&crossbar->mutex);
-	while (!crossbar->failed && crossbar->published_count <= timestep)
+	while (!crossbar->failed && crossbar->published_count <= timestep) {
 		pthread_cond_wait(&crossbar->state_available, &crossbar->mutex);
+	}
 	if (crossbar->failed) {
 		pthread_mutex_unlock(&crossbar->mutex);
 		return 1;
@@ -178,8 +214,9 @@ static int callback_data(pvecvaluesall values, int count, int ident,
 			continue;
 		}
 		const char *col = strstr(value->name, "col");
-		if (!col)
+		if (!col) {
 			continue;
+		}
 		char *end = NULL;
 		unsigned long index = strtoul(col + 3, &end, 10);
 		if (end != col + 3 &&
@@ -197,8 +234,9 @@ static int callback_data(pvecvaluesall values, int count, int ident,
 			size_t timestep = (size_t)rounded - 1;
 			int complete = 1;
 			for (size_t i = 0; i < crossbar->config.num_outputs * 2;
-			     i++)
+			     i++) {
 				complete = complete && found[i];
+			}
 			if (complete) {
 				double *decoded =
 				    crossbar->results +
@@ -213,14 +251,16 @@ static int callback_data(pvecvaluesall values, int count, int ident,
 					decoded) == 0) {
 					pthread_mutex_lock(&crossbar->mutex);
 					if (crossbar->result_count <
-					    timestep + 1)
+					    timestep + 1) {
 						crossbar->result_count =
 						    timestep + 1;
+					}
 					if (timestep + 1 <
-					    crossbar->config.num_timesteps)
+					    crossbar->config.num_timesteps) {
 						ngSpice_SetBkpt(
 						    (timestep + 2) *
 						    crossbar->config.time_step);
+					}
 					pthread_cond_broadcast(
 					    &crossbar->progress);
 					pthread_mutex_unlock(&crossbar->mutex);
@@ -238,38 +278,44 @@ int online_crossbar_init(const Online_Crossbar_Config *config,
 			 const spires_reservoir *reservoir,
 			 Online_Crossbar **crossbar_out)
 {
-	if (!config || !reservoir || !crossbar_out ||
-	    config->num_neurons == 0 || config->num_outputs == 0 ||
-	    config->num_timesteps == 0 || config->time_step <= 0.0 ||
-	    config->spike_amplitude == 0.0 || config->load_resistance <= 0.0 ||
-	    !config->model_path || !config->subcircuit_name ||
-	    !config->netlist_path)
+	if (!crossbar_out) {
 		return -1;
+	}
+	*crossbar_out = NULL;
+	if (!reservoir || !config_is_valid(config)) {
+		return -1;
+	}
 
 	Online_Crossbar *crossbar = calloc(1, sizeof(*crossbar));
-	if (!crossbar)
+	if (!crossbar) {
 		return -1;
+	}
 	crossbar->config = *config;
-	if (pthread_mutex_init(&crossbar->mutex, NULL) != 0)
+	if (pthread_mutex_init(&crossbar->mutex, NULL) != 0) {
 		goto fail;
+	}
 	crossbar->mutex_initialized = 1;
-	if (pthread_cond_init(&crossbar->state_available, NULL) != 0)
+	if (pthread_cond_init(&crossbar->state_available, NULL) != 0) {
 		goto fail;
+	}
 	crossbar->state_condition_initialized = 1;
-	if (pthread_cond_init(&crossbar->progress, NULL) != 0)
+	if (pthread_cond_init(&crossbar->progress, NULL) != 0) {
 		goto fail;
+	}
 	crossbar->progress_condition_initialized = 1;
 
 	crossbar->state_ring = calloc(2 * config->num_neurons, sizeof(double));
 	crossbar->results =
 	    calloc(config->num_timesteps * config->num_outputs, sizeof(double));
-	if (!crossbar->state_ring || !crossbar->results)
+	if (!crossbar->state_ring || !crossbar->results) {
 		goto fail;
+	}
 	if (convert_weights_to_resistances(
 		reservoir, config->num_neurons, config->num_outputs,
 		config->r_on, config->r_off, &crossbar->resistances,
-		&crossbar->mapping) != 0)
+		&crossbar->mapping) != 0) {
 		goto fail;
+	}
 
 	Crossbar_Config netlist = {.rows = config->num_neurons,
 				   .columns = config->num_outputs * 2,
@@ -283,8 +329,9 @@ int online_crossbar_init(const Online_Crossbar_Config *config,
 				   .stop_time = config->num_timesteps *
 						config->time_step,
 				   .print_state_nodes = 0};
-	if (generate_online_crossbar(config->netlist_path, &netlist) != 0)
+	if (generate_online_crossbar(config->netlist_path, &netlist) != 0) {
 		goto fail;
+	}
 
 	*crossbar_out = crossbar;
 	return 0;
@@ -296,23 +343,32 @@ fail:
 
 int online_crossbar_start(Online_Crossbar *crossbar)
 {
-	if (!crossbar || crossbar->started)
+	if (!crossbar || crossbar->started) {
 		return -1;
+	}
 	if (ngSpice_Init(callback_text, callback_text, callback_exit,
 			 callback_data, callback_init_data, callback_background,
-			 crossbar) != 0 ||
-	    ngSpice_Init_Sync(callback_voltage, NULL, NULL, NULL, crossbar) !=
-		0)
+			 crossbar) != 0) {
 		return -1;
+	}
+	if (ngSpice_Init_Sync(callback_voltage, NULL, NULL, NULL, crossbar) !=
+	    0) {
+		ngSpice_Reset();
+		return -1;
+	}
 
 	char command[4096];
-	if (snprintf(command, sizeof(command), "source %s",
-		     crossbar->config.netlist_path) >= (int)sizeof(command) ||
-	    ngSpice_Command(command) != 0)
+	int written = snprintf(command, sizeof(command), "source %s",
+			       crossbar->config.netlist_path);
+	if (written < 0 || (size_t)written >= sizeof(command) ||
+	    ngSpice_Command(command) != 0) {
+		ngSpice_Reset();
 		return -1;
+	}
 	crossbar->started = 1;
 	ngSpice_SetBkpt(crossbar->config.time_step);
 	if (ngSpice_Command("bg_run") != 0) {
+		ngSpice_Reset();
 		crossbar->started = 0;
 		return -1;
 	}
@@ -325,12 +381,15 @@ int online_crossbar_submit(Online_Crossbar *crossbar, size_t timestep,
 {
 	if (!crossbar || !state || !output_ready || !crossbar->started ||
 	    timestep >= crossbar->config.num_timesteps ||
-	    timestep != crossbar->published_count)
+	    timestep != crossbar->published_count ||
+	    (timestep != 0 && !previous_output)) {
 		return -1;
+	}
 
 	pthread_mutex_lock(&crossbar->mutex);
-	while (!crossbar->failed && timestep >= crossbar->consumed_count + 2)
+	while (!crossbar->failed && timestep >= crossbar->consumed_count + 2) {
 		pthread_cond_wait(&crossbar->progress, &crossbar->mutex);
+	}
 	if (crossbar->failed) {
 		pthread_mutex_unlock(&crossbar->mutex);
 		return -1;
@@ -343,13 +402,10 @@ int online_crossbar_submit(Online_Crossbar *crossbar, size_t timestep,
 
 	*output_ready = timestep != 0;
 	if (timestep != 0) {
-		if (!previous_output) {
-			pthread_mutex_unlock(&crossbar->mutex);
-			return -1;
-		}
-		while (!crossbar->failed && crossbar->result_count < timestep)
+		while (!crossbar->failed && crossbar->result_count < timestep) {
 			pthread_cond_wait(&crossbar->progress,
 					  &crossbar->mutex);
+		}
 		if (crossbar->failed) {
 			pthread_mutex_unlock(&crossbar->mutex);
 			return -1;
@@ -366,12 +422,14 @@ int online_crossbar_submit(Online_Crossbar *crossbar, size_t timestep,
 int online_crossbar_finish(Online_Crossbar *crossbar, double *final_output)
 {
 	if (!crossbar || !final_output ||
-	    crossbar->published_count != crossbar->config.num_timesteps)
+	    crossbar->published_count != crossbar->config.num_timesteps) {
 		return -1;
+	}
 	pthread_mutex_lock(&crossbar->mutex);
 	while (!crossbar->failed &&
-	       crossbar->result_count < crossbar->config.num_timesteps)
+	       crossbar->result_count < crossbar->config.num_timesteps) {
 		pthread_cond_wait(&crossbar->progress, &crossbar->mutex);
+	}
 	if (crossbar->failed) {
 		pthread_mutex_unlock(&crossbar->mutex);
 		return -1;
@@ -386,28 +444,35 @@ int online_crossbar_finish(Online_Crossbar *crossbar, double *final_output)
 
 void online_crossbar_destroy(Online_Crossbar *crossbar)
 {
-	if (!crossbar)
+	if (!crossbar) {
 		return;
+	}
 	if (crossbar->started && ngSpice_running()) {
 		ngSpice_Command("bg_halt");
 		if (crossbar->mutex_initialized) {
 			pthread_mutex_lock(&crossbar->mutex);
-			while (!crossbar->simulation_done && ngSpice_running())
+			while (!crossbar->simulation_done &&
+			       ngSpice_running()) {
 				pthread_cond_wait(&crossbar->progress,
 						  &crossbar->mutex);
+			}
 			pthread_mutex_unlock(&crossbar->mutex);
 		}
 	}
-	if (crossbar->started)
+	if (crossbar->started) {
 		ngSpice_Reset();
+	}
 	free(crossbar->resistances);
 	free(crossbar->state_ring);
 	free(crossbar->results);
-	if (crossbar->state_condition_initialized)
+	if (crossbar->state_condition_initialized) {
 		pthread_cond_destroy(&crossbar->state_available);
-	if (crossbar->progress_condition_initialized)
+	}
+	if (crossbar->progress_condition_initialized) {
 		pthread_cond_destroy(&crossbar->progress);
-	if (crossbar->mutex_initialized)
+	}
+	if (crossbar->mutex_initialized) {
 		pthread_mutex_destroy(&crossbar->mutex);
+	}
 	free(crossbar);
 }
diff --git a/src/online_crossbar.h b/src/online_crossbar.h
index f89a306..a27d88b 100644
--- a/src/online_crossbar.h
+++ b/src/online_crossbar.h
@@ -23,6 +23,7 @@ typedef struct {
 int online_crossbar_init(const Online_Crossbar_Config *config,
 			 const spires_reservoir *reservoir,
 			 Online_Crossbar **crossbar_out);
+
 int online_crossbar_start(Online_Crossbar *crossbar);
 
 /*
diff --git a/src/read_crossbar.c b/src/read_crossbar.c
index 5b79233..0825147 100644
--- a/src/read_crossbar.c
+++ b/src/read_crossbar.c
@@ -1,19 +1,18 @@
 #include "read_crossbar.h"
 
-#include <stdbool.h>
 #include <ngspice/sharedspice.h>
+#include <stdbool.h>
 
 #include <sched.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 int run_ngspice(const char *crossbar_path)
 {
-	if (crossbar_path == NULL) {
-		fprintf(
-		    stderr,
-		    "One of the file paths returned null when running ngspice");
+	if (!crossbar_path) {
+		fprintf(stderr, "Crossbar path is required\n");
 		return -1;
 	}
 
@@ -22,14 +21,15 @@ int run_ngspice(const char *crossbar_path)
 	    snprintf(command, sizeof(command),
 		     "ngspice -b \"%s\" > /dev/null 2>&1", crossbar_path);
 
-	if (written < 0) {
-		fprintf(stderr, "Failed to write spice command");
+	if (written < 0 || (size_t)written >= sizeof(command)) {
+		fprintf(stderr, "Could not construct ngspice command\n");
 		return -1;
 	}
 
 	int status = system(command);
-	if (status < 0) {
-		fprintf(stderr, "Failed to run ngspice command");
+	if (status != 0) {
+		fprintf(stderr, "ngspice command failed\n");
+		return -1;
 	}
 
 	return 0;
@@ -38,50 +38,68 @@ int run_ngspice(const char *crossbar_path)
 int read_crossbar(const char *data_path, size_t num_outputs,
 		  Crossbar_Output_Matrix *result)
 {
-
-	FILE *file = fopen(data_path, "r");
-	if (!file) {
-		fprintf(stderr, "Faile to open data file");
+	if (!data_path || num_outputs == 0 || !result) {
 		return -1;
 	}
 
-	// result->num_samples = 0;
-	// result->num_outputs = num_outputs;
 	result->time = NULL;
 	result->voltages = NULL;
 
-	size_t capacity = 100000;
+	FILE *file = fopen(data_path, "r");
+	if (!file) {
+		fprintf(stderr, "Failed to open crossbar data file\n");
+		return -1;
+	}
+
+	size_t capacity = 1024;
+	if (num_outputs > SIZE_MAX / capacity ||
+	    capacity * num_outputs > SIZE_MAX / sizeof(*result->voltages)) {
+		fclose(file);
+		return -1;
+	}
 
 	result->time = malloc(capacity * sizeof(*result->time));
 	result->voltages =
 	    malloc(capacity * num_outputs * sizeof(*result->voltages));
 
 	if (result->time == NULL || result->voltages == NULL) {
-		fprintf(stderr, "Failed to allocate memory for results");
-		fclose(file);
-		free_crossbar_output_matrix(result);
-		return -1;
-	}
-
-	size_t expected_fields = num_outputs * 2;
-	double *fields = malloc(expected_fields * sizeof(*fields));
-	if (fields == NULL) {
-		fprintf(stderr, "failed to allocate memory for fields");
+		fprintf(stderr, "Failed to allocate crossbar results\n");
 		fclose(file);
 		free_crossbar_output_matrix(result);
 		return -1;
 	}
 
 	char line[16384];
-	// size_t line_number = 0;
-
 	size_t sample = 0;
 	while (fgets(line, sizeof(line), file) != NULL) {
+		if (sample == capacity) {
+			if (capacity > SIZE_MAX / 2 ||
+			    capacity * 2 > SIZE_MAX / num_outputs ||
+			    capacity * 2 * num_outputs >
+				SIZE_MAX / sizeof(*result->voltages)) {
+				goto fail;
+			}
+			capacity *= 2;
+
+			double *new_times = realloc(
+			    result->time, capacity * sizeof(*result->time));
+			if (!new_times) {
+				goto fail;
+			}
+			result->time = new_times;
+
+			double *new_voltages = realloc(
+			    result->voltages,
+			    capacity * num_outputs * sizeof(*result->voltages));
+			if (!new_voltages) {
+				goto fail;
+			}
+			result->voltages = new_voltages;
+		}
+
 		char *position = line;
 		double sample_time = 0.0;
 
-		// each loop reads one time-voltage pair, saves it
-		// then moves to next loop (next time-voltage pair)
 		for (size_t output = 0; output < num_outputs; output++) {
 			double time;
 			double voltage;
@@ -89,9 +107,10 @@ int read_crossbar(const char *data_path, size_t num_outputs,
 
 			if (sscanf(position, "%lf %lf %n", &time, &voltage,
 				   &char_count) != 2) {
-				fprintf(stderr, "invalide data line");
-				fclose(file);
-				return -1;
+				fprintf(stderr,
+					"Invalid crossbar data at sample %zu\n",
+					sample);
+				goto fail;
 			}
 
 			if (output == 0) {
@@ -105,8 +124,16 @@ int read_crossbar(const char *data_path, size_t num_outputs,
 		result->time[sample] = sample_time;
 		sample++;
 	}
-	fclose(file);
+	if (ferror(file) || fclose(file) != 0) {
+		free_crossbar_output_matrix(result);
+		return -1;
+	}
 	return 0;
+
+fail:
+	fclose(file);
+	free_crossbar_output_matrix(result);
+	return -1;
 }
 
 int convert_output_to_software(size_t num_neurons, size_t num_outputs,
@@ -117,17 +144,19 @@ int convert_output_to_software(size_t num_neurons, size_t num_outputs,
 			       const double *row_voltages,
 			       double spike_amplitude, double *decoded_outputs)
 {
-	// Using differential pair mapping
-	size_t num_physical_columns;
+	(void)row_voltages;
 
-	if (!voltages || !resistances || !mapping || !decoded_outputs)
+	if (num_neurons == 0 || num_outputs == 0 || num_timesteps == 0 ||
+	    !voltages || !resistances || !mapping || !decoded_outputs) {
 		return -1;
+	}
 
 	if (load_resistance <= 0.0 || mapping->alpha == 0.0 ||
-	    spike_amplitude == 0.0)
+	    spike_amplitude == 0.0) {
 		return -1;
+	}
 
-	num_physical_columns = num_outputs * 2;
+	size_t num_physical_columns = num_outputs * 2;
 
 	for (size_t timestep = 0; timestep < num_timesteps; timestep++) {
 		for (size_t output = 0; output < num_outputs; output++) {
@@ -177,12 +206,10 @@ int convert_output_to_software(size_t num_neurons, size_t num_outputs,
 			    timestep * num_physical_columns + negative_column;
 
 			positive_voltage = voltages[positive_voltage_index];
-
 			negative_voltage = voltages[negative_voltage_index];
 
 			positive_load_current =
 			    positive_voltage / load_resistance;
-
 			negative_load_current =
 			    negative_voltage / load_resistance;
 
@@ -208,15 +235,13 @@ int convert_output_to_software(size_t num_neurons, size_t num_outputs,
 
 void free_crossbar_output_matrix(Crossbar_Output_Matrix *result)
 {
-	if (result == NULL) {
+	if (!result) {
 		return;
 	}
 
 	free(result->time);
 	free(result->voltages);
 
-	// result->num_samples = 0;
-	// result->num_outputs = 0;
 	result->time = NULL;
 	result->voltages = NULL;
 }
diff --git a/src/read_crossbar.h b/src/read_crossbar.h
index 968bc94..c6a87fa 100644
--- a/src/read_crossbar.h
+++ b/src/read_crossbar.h
@@ -5,14 +5,9 @@
 #include <stddef.h>
 
 typedef struct {
-	// size_t num_samples;
-	// size_t num_outputs;
 	double *time;
-
-	// stored in row major order
-	// voltages[sameple * num_outputs + output]
+	/* Flat row-major values: voltages[sample * num_outputs + output]. */
 	double *voltages;
-
 } Crossbar_Output_Matrix;
 
 int run_ngspice(const char *crossbar_path);
@@ -20,6 +15,10 @@ int run_ngspice(const char *crossbar_path);
 int read_crossbar(const char *data_path, size_t num_outputs,
 		  Crossbar_Output_Matrix *result);
 
+/*
+ * Decode differential crossbar voltages into software readout values.
+ * row_voltages is retained for API compatibility and is currently unused.
+ */
 int convert_output_to_software(size_t num_neurons, size_t num_outputs,
 			       size_t num_timesteps, const double *voltages,
 			       const double *resistances,
@@ -28,6 +27,7 @@ int convert_output_to_software(size_t num_neurons, size_t num_outputs,
 			       const double *row_voltages,
 			       double spike_amplitude, double *decoded_outputs);
 
+/* Release storage allocated by read_crossbar(). */
 void free_crossbar_output_matrix(Crossbar_Output_Matrix *result);
 
 #endif
diff --git a/src/spires_interface.c b/src/spires_interface.c
index 665defc..df09985 100644
--- a/src/spires_interface.c
+++ b/src/spires_interface.c
@@ -11,49 +11,57 @@ int collect_reservoir_states(spires_reservoir *reservoir,
 			     const double *input_series, size_t series_length,
 			     Reservoir_State_Matrix *result)
 {
-	// error checking
-	// RIP
+	if (!reservoir || !input_series || series_length == 0 || !result) {
+		return -1;
+	}
 
-	// clear the result first
 	result->num_samples = 0;
 	result->num_features = 0;
 	result->states = NULL;
 
 	const size_t num_inputs = spires_num_inputs(reservoir);
-
 	const size_t num_neurons = spires_num_neurons(reservoir);
+	if (num_inputs == 0 || num_neurons == 0) {
+		return -1;
+	}
 
 	if (series_length > SIZE_MAX / num_neurons ||
 	    series_length * num_neurons > SIZE_MAX / sizeof(double)) {
-		fprintf(stderr, "matrix size overloaded!!");
+		fprintf(stderr, "Reservoir state matrix is too large\n");
 		return -1;
 	}
 
 	double *states = malloc(num_neurons * series_length * sizeof(*states));
 	if (!states) {
-		fprintf(stderr, "failed to allocate memory for states");
+		fprintf(stderr, "Failed to allocate reservoir state matrix\n");
 		return -1;
 	}
 
 	spires_status status = spires_reservoir_reset(reservoir);
 	if (status != SPIRES_OK) {
-		fprintf(stderr, "reservoir reset error");
+		fprintf(stderr, "Failed to reset SPIRES reservoir\n");
 		free(states);
 		return -1;
 	}
 
-	// build state_matrix
-	for (size_t i = 0; i < series_length; i++) {
-		const double *current_input = &input_series[i * num_inputs];
+	for (size_t timestep = 0; timestep < series_length; timestep++) {
+		const double *current_input =
+		    input_series + timestep * num_inputs;
 		status = spires_step(reservoir, current_input);
 		if (status != SPIRES_OK) {
+			fprintf(stderr, "SPIRES step failed at timestep %zu\n",
+				timestep);
 			free(states);
 			return -1;
 		}
 
-		double *current_state = &states[i * num_neurons];
+		double *current_state = states + timestep * num_neurons;
 		status = spires_read_reservoir_state(reservoir, current_state);
 		if (status != SPIRES_OK) {
+			fprintf(
+			    stderr,
+			    "Failed to read reservoir state at timestep %zu\n",
+			    timestep);
 			free(states);
 			return -1;
 		}
@@ -72,29 +80,48 @@ int convert_weights_to_resistances(const spires_reservoir *reservoir,
 				   double **resistances_out,
 				   conductance_mapping *mapping)
 {
-	double max_abs_weight = 0.0;
+	if (!reservoir || num_neurons == 0 || num_outputs == 0 || r_on <= 0.0 ||
+	    r_off <= r_on || !resistances_out || !mapping) {
+		return -1;
+	}
 
 	*resistances_out = NULL;
+	if (num_outputs > SIZE_MAX / 2 ||
+	    num_neurons > SIZE_MAX / num_outputs) {
+		return -1;
+	}
+
 	size_t weight_count = num_neurons * num_outputs;
 	size_t num_physical_columns = num_outputs * 2;
+	if (num_neurons > SIZE_MAX / num_physical_columns ||
+	    num_neurons * num_physical_columns > SIZE_MAX / sizeof(double)) {
+		return -1;
+	}
 
-	double *readout = malloc(num_neurons * num_outputs * sizeof(double));
-
-	spires_read_readout(reservoir, readout);
+	double *readout = malloc(weight_count * sizeof(*readout));
+	if (!readout) {
+		fprintf(stderr, "Failed to allocate readout weights\n");
+		return -1;
+	}
+	if (spires_read_readout(reservoir, readout) != SPIRES_OK) {
+		fprintf(stderr, "Failed to read SPIRES readout weights\n");
+		free(readout);
+		return -1;
+	}
 
 	double *resistances =
-	    malloc(num_neurons * num_physical_columns * sizeof(double));
-	if (resistances == NULL) {
-		fprintf(stderr, "Failed to allocated crossbar resistances");
+	    malloc(num_neurons * num_physical_columns * sizeof(*resistances));
+	if (!resistances) {
+		fprintf(stderr, "Failed to allocate crossbar resistances\n");
 		free(readout);
 		return -1;
 	}
 
-	// get the max weight
+	double max_abs_weight = 0.0;
 	for (size_t i = 0; i < weight_count; i++) {
 		if (!isfinite(readout[i])) {
 			fprintf(stderr,
-				"invalid readout weight at index %zu: %g\n", i,
+				"Invalid readout weight at index %zu: %g\n", i,
 				readout[i]);
 			free(readout);
 			free(resistances);
@@ -106,15 +133,20 @@ int convert_weights_to_resistances(const spires_reservoir *reservoir,
 			max_abs_weight = abs_weight;
 		}
 	}
+	if (max_abs_weight == 0.0) {
+		fprintf(stderr,
+			"Cannot map an all-zero readout to resistances\n");
+		free(readout);
+		free(resistances);
+		return -1;
+	}
 
 	mapping->g_min = 1.0 / r_off;
 	mapping->g_max = 1.0 / r_on;
 	mapping->max_abs_weight = max_abs_weight;
 
-	// calculate the alpha scaling parameter to normalize the weights
 	mapping->alpha = (mapping->g_max - mapping->g_min) / max_abs_weight;
 
-	// differential pair mapping
 	for (size_t neuron = 0; neuron < num_neurons; neuron++) {
 		for (size_t output = 0; output < num_outputs; output++) {
 			size_t weight_index = output * num_neurons + neuron;
@@ -133,8 +165,7 @@ int convert_weights_to_resistances(const spires_reservoir *reservoir,
 				positive_conductance =
 				    mapping->g_min + mapping->alpha * weight;
 				negative_conductance = mapping->g_min;
-			}
-			if (weight < 0.0) {
+			} else {
 				positive_conductance = mapping->g_min;
 				negative_conductance =
 				    mapping->g_min + mapping->alpha * (-weight);
@@ -146,10 +177,6 @@ int convert_weights_to_resistances(const spires_reservoir *reservoir,
 			    1.0 / negative_conductance;
 		}
 	}
-	// printf("max absolute weight = %.12e\n", mapping->max_abs_weight);
-	// printf("alpha = %.12e\n", mapping->alpha);
-	// printf("physical crossbar dimensions: %zu x %zu\n", num_neurons,
-	//        num_physical_columns);
 
 	*resistances_out = resistances;
 	free(readout);
@@ -160,12 +187,16 @@ int convert_weights_to_resistances(const spires_reservoir *reservoir,
 int train_reservoir(spires_reservoir *reservoir, double *input_series,
 		    double *target_series, size_t series_length, double lambda)
 {
-	spires_status status =
-	    spires_train_ridge(reservoir, (double *)input_series,
-			       (double *)target_series, series_length, lambda);
+	if (!reservoir || !input_series || !target_series ||
+	    series_length == 0 || lambda < 0.0) {
+		return -1;
+	}
+
+	spires_status status = spires_train_ridge(
+	    reservoir, input_series, target_series, series_length, lambda);
 
 	if (status != SPIRES_OK) {
-		fprintf(stderr, "Spires ridge training failed");
+		fprintf(stderr, "SPIRES ridge training failed\n");
 		return -1;
 	}
 
@@ -179,7 +210,6 @@ void free_reservoir_state_matrix(Reservoir_State_Matrix *matrix)
 	}
 
 	free(matrix->states);
-
 	matrix->states = NULL;
 	matrix->num_samples = 0;
 	matrix->num_features = 0;
diff --git a/src/spires_interface.h b/src/spires_interface.h
index 006b9d7..f3552b9 100644
--- a/src/spires_interface.h
+++ b/src/spires_interface.h
@@ -5,8 +5,9 @@
 #include <stddef.h>
 
 typedef struct {
-	size_t num_samples; // number of time steps
+	size_t num_samples;
 	size_t num_features;
+	/* Row-major continuous reservoir states: [sample][feature]. */
 	double *states;
 } Reservoir_State_Matrix;
 
@@ -21,8 +22,9 @@ int collect_reservoir_states(spires_reservoir *reservoir,
 			     const double *input_series, size_t series_length,
 			     Reservoir_State_Matrix *result);
 
+/* Train the SPIRES-owned readout using its configured state representation. */
 int train_reservoir(spires_reservoir *reservoir, double *input_series,
-		    double *taret_series, size_t series_length, double lambda);
+		    double *target_series, size_t series_length, double lambda);
 
 int convert_weights_to_resistances(const spires_reservoir *reservoir,
 				   size_t num_neurons, size_t num_outputs,
@@ -30,6 +32,7 @@ int convert_weights_to_resistances(const spires_reservoir *reservoir,
 				   double **resistances_out,
 				   conductance_mapping *mapping);
 
+/* Release storage allocated by collect_reservoir_states(). */
 void free_reservoir_state_matrix(Reservoir_State_Matrix *matrix);
 
 #endif