Harm osc will write log to stdout.

modsim/ass3/harm_osc.c

@@ -7,23 +7,18 @@
 #define DT .001
 
 #define INTEGRATE(method, t0, t1, FN) { \
-    if( method(t0, t1, DT, y0, y1, 2, &f_ ## FN, args_ ## FN) ) \
-        puts("FAIL"); \
-    else \
-        printf("y1 using %-12s s:%.10f\n", #method ":", *y1); \
+    method(t0, t1, DT, y0, y1, 2, &f_ ## FN, args_ ## FN); \
+    /*if( method(t0, t1, DT, y0, y1, 2, &f_ ## FN, args_ ## FN) ) puts("FAIL");*/ \
+    /* else printf("y1 using %-12s s:%.10f\n", #method ":", *y1); */\
 }
+
 #define COMPARE(t0, t1, fn) { \
-    printf("Function %s\n", #fn); \
+    /*printf("Function %s\n", #fn);*/ \
     INTEGRATE(Euler, t0, t1, fn); \
     INTEGRATE(RungeKutta2, t0, t1, fn); \
     INTEGRATE(RungeKutta4, t0, t1, fn); \
 }
 
-//void log(double t, double *y) {
-//    printf("%f,%f,%f\n", t, y[0], y[1]);
-//}
-//
-
 #define PARAM(n) ((double *) params)[n]
 
 int f_osc(double t, double *y, double *dy, void *params) {
@@ -73,12 +68,14 @@ int main(void) {
     COMPARE(.0, 10.0, forced_osc);
 
     // TODO: this model is not yet completed.
-    printf("Function: lottka_volt\n");
+    //printf("Function: lottka_volt\n");
     INTEGRATE(RungeKutta4, .0, 10.0, lottka_volt);
 
     // TODO: this model is not yet completed.
-    printf("Function: modified_pp\n");
+    //printf("Function: modified_pp\n");
     INTEGRATE(RungeKutta4, .0, 10.0, modified_pp);
 
+    logger_close();
+
     return 0;
 }

modsim/ass3/logger.c

@@ -2,12 +2,24 @@
 
 FILE *logfile = NULL;
 
-void logger(double t, double *y) {
-    if( !logfile ) {
-        logfile = fopen("methods.log", "w");
-    }
+void logger_open(const char* filename) {
+    if( logfile )
+        logger_close();
+    logfile = fopen(filename, "w");
+}
 
-    fprintf(logfile, "%e,%e\n", t, y[0]);
+void logger(double t, int N, double *y) {
+    if( !logfile )
+        logfile = stdout;
+
+    fprintf(logfile, "%e", t);
+    if( N > 0 ) {
+        for( int i = 0; i < N - 1; i++ )
+            fprintf(logfile, ",%e", y[0]);
+        fprintf(logfile, "%e\n", y[N-1]);
+    }
+    else
+        fprintf(logfile, "\n");
 }
 
 void logger_close() {

modsim/ass3/logger.h

@@ -6,7 +6,7 @@
 
 //typedef void (*log_function)(double t, double *y);
 
-void logger(double t, double *y);
+void logger(double t, int N, double *y);
 void logger_close();
 
 #endif // __LOG_H__

modsim/ass3/methods.c

@@ -28,7 +28,7 @@ int Euler(double t0, double t1, double dt, double *y0, double *y1, int N,
     for( j = 0; j < N; j++ )
         y1[j] = y0[j];
 
-    logger(t0, y0);
+    logger(t0, N, y0);
 
     // Estimate for each interval
     for( i = 0; i < intervals; i++ ) {
@@ -41,7 +41,7 @@ int Euler(double t0, double t1, double dt, double *y0, double *y1, int N,
             y1[j] = y1[j] + dy[j] * dt;
 
         // Value can be printed/logged here
-        logger(t, y1);
+        logger(t, N, y1);
 
         t = t0 + i * dt;
     }
@@ -58,7 +58,7 @@ int RungeKutta2(double t0, double t1, double dt, double *y0, double *y1, int N,
     for( j = 0; j < N; j++ )
         y1[j] = y0[j];
 
-    logger(t0, y0);
+    logger(t0, N, y0);
 
     // Estimate for each interval
     for( i = 0; i < intervals; i++ ) {
@@ -71,7 +71,7 @@ int RungeKutta2(double t0, double t1, double dt, double *y0, double *y1, int N,
             y1[j] = y1[j] + .5 * (dy1[j] + dy2[j]) * dt;
 
         // Value can be printed/logged here
-        logger(t, y1);
+        logger(t, N, y1);
 
         t = t0 + i * dt;
     }
@@ -88,7 +88,7 @@ int RungeKutta4(double t0, double t1, double dt, double *y0, double *y1, int N,
     for( j = 0; j < N; j++ )
         y[j] = y1[j] = y0[j];
 
-    logger(t0, y0);
+    logger(t0, N, y0);
 
     // Estimate for each interval
     for( i = 0; i < intervals; i++ ) {
@@ -133,7 +133,7 @@ int RungeKutta4(double t0, double t1, double dt, double *y0, double *y1, int N,
         }
 
         // Value can be printed/logged here
-        logger(t, y1);
+        logger(t, N, y1);
 
         t = t0 + i * dt;
     }