Added sources files for part 2 of modsim assignment 4.

modsim/ass4_sander/part2/Makefile

+CFLAGS +=-std=c99 -Wall -Wextra -g -O2 -pthread
+LDFLAGS+=-pthread -lmpi -lopen-rte -lopen-pal -ldl -Wl,--export-dynamic \
+		 -lnsl -lutil -lm -ldl
+
+MAIN   = main
+OFILES = $($(wildcard *.c):.c=.o)
+
+$(MAIN): $(OFILES)
+
+clean:
+	rm -vf $(MAIN) $(OFILES)
+
+check-syntax:
+	$(CXX) $(CXXFLAGS) -fsyntax-only ${CHK_SOURCES}

modsim/ass4_sander/part2/main.c

+#include <math.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#define GRID_LENGTH 64
+
+double Y[GRID_LENGTH][3];
+int t_next, t_prev, t_cur;
+
+void init_sinus(char **argv) {
+    double amp;
+    int h_phases;
+
+    sscanf(argv[2], "%lf", &amp);
+    sscanf(argv[3], "%i", &h_phases);
+    for( int i = 0; i < GRID_LENGTH; i++ ) {
+        Y[i][t] = amp * sin(M_PI * (i(double)/(double)GRID_LENGTH) * h_phases);
+    }
+}
+
+void init_pluck(char **argv) {
+    double amp, position;
+    int ipos, i;
+
+    sscanf(argv[2], "%lf", &amp);
+    sscanf(argv[3], "%i", &position);
+
+    ipos = position / dx * GRID_LENGTH;
+
+    for( i = 0; i < ipos; i++ ) {
+        Y[i][t] = i * dx / position * amp;
+    }
+    for(;i < GRID_LENGTH; i++ ) {
+        Y[i][t] = ((GRID_LENGTH - i) * dx) / (GRID_LENGTH - ipos) * amp;
+    }
+}
+
+void iterate(double C, int t_prev, int t_cur, int t_next) {
+    for( int i = 1; i < GRID_LENGTH; i++ ) {
+        Y[i][t_next] = C * (Y[i-1][t_cur] - 2*Y[i][t_cur] + Y[i+1][t_cur])
+            - Y[i][t_prev]
+            + 2 * Y[i][t_cur];
+    }
+}
+
+#define SWAP(a, b) \
+    a ^= b; \
+    b ^= a; \
+    a ^= b;
+
+
+void plot(int col) {
+    printf("%f", Y[0][col]);
+    for( int i = 1; i < GRID_LENGTH; i++ )
+        printf(",%f", Y[i][col]);
+    printf("\n");
+}
+
+int main(int argc, char**argv) {
+
+    if(argc < 4) {
+        fprintf(stderr, "Usage: %s <p amplitude position |s amplitude phases", argv[0]);
+        return 1;
+    }
+
+    switch(*argv[1]) {
+    case 'p': init_pluck(argv); break;
+    case 's': init_sinus(argv); break;
+    default:
+        fprintf(stderr, "Does this look like a 'p' or 's' to you?\n");
+        return 1;
+    }
+
+    double c = .04, dt = .1, dx = .02,
+        C = c * c * (dt/dx) * (dt/dx);
+
+    // TODO: implement iterations
+    int t_prev = 0, t_cur = 1, t_next = 2,
+        T = 10;
+
+    for( int i = 0; i < T; i++ ) {
+        iterate(C, t_prev, t_cur, t_next);
+        SWAP(t_cur, t_next);
+        SWAP(t_prev, t_next);
+        plot(t_cur);
+    }
+
+    return 0;
+}

modsim/ass4_sander/part2/plot.py

+from pyplot import show, fig
+