Subroutine */
| 7899 | } /* dscal_ */ |
| 7900 | |
| 7901 | /* Subroutine */ int dswap_(integer *n, doublereal *dx, integer *incx, |
| 7902 | doublereal *dy, integer *incy) |
| 7903 | { |
| 7904 | /* System generated locals */ |
| 7905 | integer i__1; |
| 7906 | |
| 7907 | /* Local variables */ |
| 7908 | static integer i__, m, ix, iy, mp1; |
| 7909 | static doublereal dtemp; |
| 7910 | |
| 7911 | |
| 7912 | /* |
| 7913 | Purpose |
| 7914 | ======= |
| 7915 | |
| 7916 | interchanges two vectors. |
| 7917 | uses unrolled loops for increments equal one. |
| 7918 | |
| 7919 | Further Details |
| 7920 | =============== |
| 7921 | |
| 7922 | jack dongarra, linpack, 3/11/78. |
| 7923 | modified 12/3/93, array(1) declarations changed to array(*) |
| 7924 | |
| 7925 | ===================================================================== |
| 7926 | */ |
| 7927 | |
| 7928 | /* Parameter adjustments */ |
| 7929 | --dy; |
| 7930 | --dx; |
| 7931 | |
| 7932 | /* Function Body */ |
| 7933 | if (*n <= 0) { |
| 7934 | return 0; |
| 7935 | } |
| 7936 | if (*incx == 1 && *incy == 1) { |
| 7937 | goto L20; |
| 7938 | } |
| 7939 | |
| 7940 | /* |
| 7941 | code for unequal increments or equal increments not equal |
| 7942 | to 1 |
| 7943 | */ |
| 7944 | |
| 7945 | ix = 1; |
| 7946 | iy = 1; |
| 7947 | if (*incx < 0) { |
| 7948 | ix = (-(*n) + 1) * *incx + 1; |
| 7949 | } |
| 7950 | if (*incy < 0) { |
| 7951 | iy = (-(*n) + 1) * *incy + 1; |
| 7952 | } |
| 7953 | i__1 = *n; |
| 7954 | for (i__ = 1; i__ <= i__1; ++i__) { |
| 7955 | dtemp = dx[ix]; |
| 7956 | dx[ix] = dy[iy]; |
| 7957 | dy[iy] = dtemp; |
| 7958 | ix += *incx; |