svn-gvsig-desktop / tags / gvsig_topologia-0_1_0-1232 / libraries / libjni-proj4 / src / biveval.c @ 45670
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/* procedures for evaluating Tseries */
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#ifndef lint
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static const char SCCSID[]="@(#)biveval.c 4.4 93/06/12 GIE REL"; |
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#endif
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# include <projects.h> |
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# define NEAR_ONE 1.00001 |
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static projUV
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w2, w; |
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static double ceval(struct PW_COEF *C, int n) { |
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double d=0, dd=0, vd, vdd, tmp, *c; |
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int j;
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for (C += n ; n-- ; --C ) {
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if (j = C->m) {
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vd = vdd = 0.;
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for (c = C->c + --j; j ; --j ) {
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vd = w2.v * (tmp = vd) - vdd + *c--; |
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vdd = tmp; |
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} |
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d = w2.u * (tmp = d) - dd + w.v * vd - vdd + 0.5 * *c; |
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} else
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d = w2.u * (tmp = d) - dd; |
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dd = tmp; |
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} |
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if (j = C->m) {
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vd = vdd = 0.;
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for (c = C->c + --j; j ; --j ) {
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vd = w2.v * (tmp = vd) - vdd + *c--; |
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vdd = tmp; |
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} |
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return (w.u * d - dd + 0.5 * ( w.v * vd - vdd + 0.5 * *c )); |
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} else
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return (w.u * d - dd);
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} |
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projUV /* bivariate Chebyshev polynomial entry point */
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bcheval(projUV in, Tseries *T) {
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projUV out; |
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/* scale to +-1 */
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w.u = ( in.u + in.u - T->a.u ) * T->b.u; |
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w.v = ( in.v + in.v - T->a.v ) * T->b.v; |
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if (fabs(w.u) > NEAR_ONE || fabs(w.v) > NEAR_ONE) {
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out.u = out.v = HUGE_VAL; |
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pj_errno = -36;
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} else { /* double evaluation */ |
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w2.u = w.u + w.u; |
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w2.v = w.v + w.v; |
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out.u = ceval(T->cu, T->mu); |
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out.v = ceval(T->cv, T->mv); |
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} |
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return out;
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} |
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projUV /* bivariate power polynomial entry point */
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bpseval(projUV in, Tseries *T) {
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projUV out; |
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double *c, row;
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int i, m;
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out.u = out.v = 0.;
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for (i = T->mu; i >= 0; --i) { |
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row = 0.;
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if (m = T->cu[i].m) {
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c = T->cu[i].c + m; |
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while (m--)
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row = *--c + in.v * row; |
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} |
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out.u = row + in.u * out.u; |
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} |
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for (i = T->mv; i >= 0; --i) { |
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row = 0.;
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if (m = T->cv[i].m) {
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c = T->cv[i].c + m; |
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while (m--)
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row = *--c + in.v * row; |
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} |
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out.v = row + in.u * out.v; |
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} |
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return out;
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} |
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projUV /* general entry point selecting evaluation mode */
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biveval(projUV in, Tseries *T) {
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if (T->power) {
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return bpseval(in, T);
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} else {
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return bcheval(in, T);
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} |
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} |
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