diff options
Diffstat (limited to 'src/bch2bps.c')
| -rw-r--r-- | src/bch2bps.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/src/bch2bps.c b/src/bch2bps.c new file mode 100644 index 00000000..0d773575 --- /dev/null +++ b/src/bch2bps.c @@ -0,0 +1,143 @@ +/* convert bivariate w Chebyshev series to w Power series */ +#ifndef lint +static const char SCCSID[]="@(#)bch2bps.c 4.5 94/03/22 GIE REL"; +#endif +#include <projects.h> +/* basic support procedures */ + static void /* clear vector to zero */ +clear(UV *p, int n) { static const UV c = {0., 0.}; while (n--) *p++ = c; } + static void /* clear matrix rows to zero */ +bclear(UV **p, int n, int m) { while (n--) clear(*p++, m); } + static void /* move vector */ +bmove(UV *a, UV *b, int n) { while (n--) *a++ = *b++; } + static void /* a <- m * b - c */ +submop(UV *a, double m, UV *b, UV *c, int n) { + while (n--) { + a->u = m * b->u - c->u; + a++->v = m * b++->v - c++->v; + } +} + static void /* a <- b - c */ +subop(UV *a, UV *b, UV *c, int n) { + while (n--) { + a->u = b->u - c->u; + a++->v = b++->v - c++->v; + } +} + static void /* multiply vector a by scalar m */ +dmult(UV *a, double m, int n) { while(n--) { a->u *= m; a->v *= m; ++a; } } + static void /* row adjust a[] <- a[] - m * b[] */ +dadd(UV *a, UV *b, double m, int n) { + while(n--) { + a->u -= m * b->u; + a++->v -= m * b++->v; + } +} + static void /* convert row to pover series */ +rows(UV *c, UV *d, int n) { + UV sv, *dd; + int j, k; + + dd = (UV *)vector1(n-1, sizeof(UV)); + sv.u = sv.v = 0.; + for (j = 0; j < n; ++j) d[j] = dd[j] = sv; + d[0] = c[n-1]; + for (j = n-2; j >= 1; --j) { + for (k = n-j; k >= 1; --k) { + sv = d[k]; + d[k].u = 2. * d[k-1].u - dd[k].u; + d[k].v = 2. * d[k-1].v - dd[k].v; + dd[k] = sv; + } + sv = d[0]; + d[0].u = -dd[0].u + c[j].u; + d[0].v = -dd[0].v + c[j].v; + dd[0] = sv; + } + for (j = n-1; j >= 1; --j) { + d[j].u = d[j-1].u - dd[j].u; + d[j].v = d[j-1].v - dd[j].v; + } + d[0].u = -dd[0].u + .5 * c[0].u; + d[0].v = -dd[0].v + .5 * c[0].v; + pj_dalloc(dd); +} + static void /* convert columns to power series */ +cols(UV **c, UV **d, int nu, int nv) { + UV *sv, **dd; + int j, k; + + dd = (UV **)vector2(nu, nv, sizeof(UV)); + sv = (UV *)vector1(nv, sizeof(UV)); + bclear(d, nu, nv); + bclear(dd, nu, nv); + bmove(d[0], c[nu-1], nv); + for (j = nu-2; j >= 1; --j) { + for (k = nu-j; k >= 1; --k) { + bmove(sv, d[k], nv); + submop(d[k], 2., d[k-1], dd[k], nv); + bmove(dd[k], sv, nv); + } + bmove(sv, d[0], nv); + subop(d[0], c[j], dd[0], nv); + bmove(dd[0], sv, nv); + } + for (j = nu-1; j >= 1; --j) + subop(d[j], d[j-1], dd[j], nv); + submop(d[0], .5, c[0], dd[0], nv); + freev2(dd, nu); + pj_dalloc(sv); +} + static void /* row adjust for range -1 to 1 to a to b */ +rowshft(double a, double b, UV *d, int n) { + int k, j; + double fac, cnst; + + cnst = 2. / (b - a); + fac = cnst; + for (j = 1; j < n; ++j) { + d[j].u *= fac; + d[j].v *= fac; + fac *= cnst; + } + cnst = .5 * (a + b); + for (j = 0; j <= n-2; ++j) + for (k = n - 2; k >= j; --k) { + d[k].u -= cnst * d[k+1].u; + d[k].v -= cnst * d[k+1].v; + } +} + static void /* column adjust for range -1 to 1 to a to b */ +colshft(double a, double b, UV **d, int n, int m) { + int k, j; + double fac, cnst; + + cnst = 2. / (b - a); + fac = cnst; + for (j = 1; j < n; ++j) { + dmult(d[j], fac, m); + fac *= cnst; + } + cnst = .5 * (a + b); + for (j = 0; j <= n-2; ++j) + for (k = n - 2; k >= j; --k) + dadd(d[k], d[k+1], cnst, m); +} + int /* entry point */ +bch2bps(UV a, UV b, UV **c, int nu, int nv) { + UV **d; + int i; + + if (nu < 1 || nv < 1 || !(d = (UV **)vector2(nu, nv, sizeof(UV)))) + return 0; + /* do rows to power series */ + for (i = 0; i < nu; ++i) { + rows(c[i], d[i], nv); + rowshft(a.v, b.v, d[i], nv); + } + /* do columns to power series */ + cols(d, c, nu, nv); + colshft(a.u, b.u, c, nu, nv); + freev2(d, nu); + return 1; +} |