131 lines
4.3 KiB
C
131 lines
4.3 KiB
C
/* This entire routine written by PW. */
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#include <stdio.h>
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#include <string.h>
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#include "xgraph.h"
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void
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Der1()
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{
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PointList *theList, *D1List, *D2List;
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double m,b;
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int i;
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for (i=0;i<MAXSETS;i++) {
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theList = PlotData[i].list;
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if (theList) {
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DataD1[i].list = (PointList *)malloc(sizeof(PointList));
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DataD2[i].list = (PointList *)malloc(sizeof(PointList));
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D1List = DataD1[i].list;
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D2List = DataD2[i].list;
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} else
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DataD1[i].list = DataD2[i].list = NULL;
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DataD1[i].setName =
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(char *)malloc(sizeof(char)*strlen(PlotData[i].setName));
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DataD2[i].setName =
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(char *)malloc(sizeof(char)*strlen(PlotData[i].setName));
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strcpy(DataD1[i].setName,PlotData[i].setName);
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strcpy(DataD2[i].setName,PlotData[i].setName);
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while (theList) {
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int j;
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D1List->numPoints = D2List->numPoints = theList->numPoints;
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D1List->xvec = (double *)malloc(sizeof(double)*theList->numPoints);
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D1List->yvec = (double *)malloc(sizeof(double)*theList->numPoints);
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D1List->next = NULL;
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D2List->xvec = (double *)malloc(sizeof(double)*theList->numPoints);
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D2List->yvec = (double *)malloc(sizeof(double)*theList->numPoints);
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D2List->next = NULL;
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for (j=1;j<theList->numPoints-1;j++) {
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D1List->xvec[j] = D2List->xvec[j] = theList->xvec[j];
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D1List->yvec[j] = (theList->yvec[j+1] - theList->yvec[j-1]) /
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(theList->xvec[j+1] - theList->xvec[j-1]);
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D2List->yvec[j] = (theList->yvec[j+1] + theList->yvec[j-1] -
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2.0*theList->yvec[j]) /
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((theList->xvec[j+1] - theList->xvec[j]) *
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(theList->xvec[j]-theList->xvec[j-1]));
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}
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/* Extrapolate to get the endpoints ... */
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/* end near 0 */
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D1List->xvec[0] = theList->xvec[0];
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D1List->xvec[theList->numPoints-1] =
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theList->xvec[theList->numPoints-1];
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m = (D1List->yvec[2]-D1List->yvec[1]) /
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(theList->xvec[2]-theList->xvec[1]);
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b = D1List->yvec[1] - m*theList->xvec[1];
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D1List->yvec[0] = m*theList->xvec[0] + b;
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/* end near numPoints-1 */
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m = (D1List->yvec[theList->numPoints-2]-
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D1List->yvec[theList->numPoints-3]) /
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(theList->xvec[theList->numPoints-2]-
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theList->xvec[theList->numPoints-3]);
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b = D1List->yvec [theList->numPoints-2] -
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m*theList->xvec[theList->numPoints-2];
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D1List->yvec[theList->numPoints-1] =
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m*theList->xvec[theList->numPoints-1] + b;
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/* Extrapolate to get the endpoints ... */
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/* end near 0 */
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D2List->xvec[0] = theList->xvec[0];
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D2List->xvec[theList->numPoints-1] =
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theList->xvec[theList->numPoints-1];
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m = (D2List->yvec[2]-D2List->yvec[1]) /
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(theList->xvec[2]-theList->xvec[1]);
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b = D2List->yvec[1] - m*theList->xvec[1];
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D2List->yvec[0] = m*theList->xvec[0] + b;
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/* end near numPoints-1 */
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m = (D2List->yvec[theList->numPoints-2]-
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D2List->yvec[theList->numPoints-3]) /
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(theList->xvec[theList->numPoints-2]-
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theList->xvec[theList->numPoints-3]);
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b = D2List->yvec[theList->numPoints-2] -
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m*theList->xvec[theList->numPoints-2];
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D2List->yvec[theList->numPoints-1] =
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m*theList->xvec[theList->numPoints-1] + b;
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theList = theList->next;
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if (theList) {
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D1List->next = (PointList *)malloc(sizeof(PointList));
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D2List->next = (PointList *)malloc(sizeof(PointList));
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D1List = D1List->next;
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D2List = D2List->next;
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}
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}
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}
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}
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void
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Bounds(loX, loY, hiX, hiY, Ord)
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double *loX, *loY, *hiX, *hiY;
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int Ord;
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{
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int i;
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PointList *theList;
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if ((Ord<1) || (Ord>2)) {
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printf ("Internal Error - Cannot eval deriv > 2 in Bounds.\n");
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exit(1);
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}
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*loX = *loY = *hiX = *hiY = 0.0;
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for (i=0;i<MAXSETS;i++) {
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if (Ord == 1)
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theList = DataD1[i].list;
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else
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theList = DataD2[i].list;
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while (theList) {
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int j;
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for (j=0;j<theList->numPoints;j++) {
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*loX = (theList->xvec[j]<*loX?theList->xvec[j]:*loX);
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*loY = (theList->yvec[j]<*loY?theList->yvec[j]:*loY);
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*hiX = (theList->xvec[j]>*hiX?theList->xvec[j]:*hiX);
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*hiY = (theList->yvec[j]>*hiY?theList->yvec[j]:*hiY);
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}
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theList = theList->next;
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}
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}
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}
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