add

213.c

@@ -0,0 +1,115 @@
+// This program solves the LP problem on p. 99 of the O.R. book by Taha.
+
+#include <stdio.h>
+
+#define NROW 4	// including the Z row
+#define NCOL 8	// including the solution column
+
+char *var[NCOL] = {"r", "X1", "X2", "S1", "S2", "R1", "R2", "Sol'n"};
+
+int basic[NROW] = {0, 5, 6, 4}; // r, R1, R2, S2
+
+//	Basic	r	X1	X2	S1	S2	R1	R2	Sol'n
+//	r	1	7	4	-1	0	0	0	9
+//	R1	0	3	1	0	0	1	0	3
+//	R2	0	4	3	-1	0	0	1	6
+//	S2	0	1	2	0	1	0	0	4
+
+double c[NROW][NCOL] = {
+	{1,	7,	4,	-1,	0,	0,	0,	9},
+	{0,	3,	1,	0,	0,	1,	0,	3},
+	{0,	4,	3,	-1,	0,	0,	1,	6},
+	{0,	1,	2,	0,	1,	0,	0,	4},
+};
+
+main()
+{
+	int i, j, k, pivot_row, pivot_column, iteration = 0;
+	double s, t, pivot_element;
+
+	while (1) {
+
+		// print the tableau
+
+		printf("\nIteration %d\n\n", iteration++);
+		printf("%-8s", "Basic");
+		for (i = 0; i < NCOL; i++)
+			printf("%-8s", var[i]);
+		printf("\n");
+		for (i = 0; i < NROW; i++) {
+			printf("%-8s", var[basic[i]]);
+			for (j = 0; j < NCOL; j++)
+				printf("%-8g", c[i][j]);
+			printf("\n");
+		}
+		printf("\n");
+
+		// find the entering variable (most positive non-basic variable)
+
+		pivot_column = 0;
+		for (i = 1; i < NCOL - 1; i++) {
+			// check to see if "i" is a basic variable
+			for (j = 1; j < NROW; j++)
+				if (basic[j] == i)
+					break;
+			if (j < NROW)
+				continue; // it's a basic variable
+			if (pivot_column == 0 || c[0][i] > c[0][pivot_column])
+				pivot_column = i;
+		}
+
+		// if non-positive then done
+
+		if (c[0][pivot_column] <= 0) {
+			printf("done\n");
+			break;
+		}
+
+		printf("%s is the entering variable\n", var[pivot_column]);
+
+		// find the leaving variable
+
+		pivot_row = 0;
+		for (i = 1; i < NROW; i++) {
+			if (c[i][pivot_column] <= 0.0)
+				continue;
+			t = c[i][NCOL - 1] / c[i][pivot_column];
+			if (pivot_row == 0 || t < s) {
+				s = t;
+				pivot_row = i;
+			}
+		}
+
+		if (pivot_row == 0) {
+			printf("cannot determine the leaving variable\n");
+			exit(0);
+		}
+
+		printf("%s is the leaving variable\n", var[basic[pivot_row]]);
+
+		pivot_element = c[pivot_row][pivot_column];
+
+		// new pivot row
+
+		for (i = 0; i < NCOL; i++)
+			c[pivot_row][i] /= pivot_element;
+
+		// other rows
+
+		for (i = 0; i < NROW; i++) {
+			if (i == pivot_row)
+				continue;
+			t = c[i][pivot_column];
+			for (j = 0; j < NCOL; j++) {
+				s = c[i][j] - t * c[pivot_row][j];
+				if (-1e-10 < s && s < 1e-10)
+					s = 0.0; // clip
+				c[i][j]  = s;
+			}
+		}
+
+		// new basic variable
+
+		basic[pivot_row] = pivot_column;
+	}
+}

214.c

@@ -0,0 +1,26 @@
+// Convert TXT to TeX.
+
+#include <stdio.h>
+
+main(int argc, char *argv[])
+{
+	int c;
+	FILE *f;
+	f = fopen(argv[1], "r");
+	printf("\\tt\n");
+	printf("\\nopagenumbers\n");
+	printf("\\obeylines\n");
+	printf("\\obeyspaces\n");
+	while (1) {
+		c = fgetc(f);
+		if (c < 0)
+			break;
+		if (c == '\n')
+			printf("\n");
+		else if (c == ' ')
+			printf("\\ ");
+		else
+			printf("\\char%d", c);
+	}
+	printf("\\vfill\\end\n");
+}