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143 lines
5.1 KiB
Fortran
143 lines
5.1 KiB
Fortran
*DECK PASSB5
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SUBROUTINE PASSB5 (IDO, L1, CC, CH, WA1, WA2, WA3, WA4)
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C***BEGIN PROLOGUE PASSB5
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C***SUBSIDIARY
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C***PURPOSE Calculate the fast Fourier transform of subvectors of
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C length five.
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C***LIBRARY SLATEC (FFTPACK)
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C***TYPE SINGLE PRECISION (PASSB5-S)
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C***AUTHOR Swarztrauber, P. N., (NCAR)
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C***ROUTINES CALLED (NONE)
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C***REVISION HISTORY (YYMMDD)
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C 790601 DATE WRITTEN
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C 830401 Modified to use SLATEC library source file format.
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C 860115 Modified by Ron Boisvert to adhere to Fortran 77 by
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C (a) changing dummy array size declarations (1) to (*),
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C (b) changing definition of variables PI, TI11, TI12,
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C TR11, TR12 by using FORTRAN intrinsic functions ATAN
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C and SIN instead of DATA statements.
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C 881128 Modified by Dick Valent to meet prologue standards.
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C 890831 Modified array declarations. (WRB)
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C 891214 Prologue converted to Version 4.0 format. (BAB)
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C 900402 Added TYPE section. (WRB)
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C***END PROLOGUE PASSB5
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DIMENSION CC(IDO,5,*), CH(IDO,L1,5), WA1(*), WA2(*), WA3(*),
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+ WA4(*)
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C***FIRST EXECUTABLE STATEMENT PASSB5
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PI = 4.*ATAN(1.)
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TR11 = SIN(.1*PI)
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TI11 = SIN(.4*PI)
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TR12 = -SIN(.3*PI)
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TI12 = SIN(.2*PI)
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IF (IDO .NE. 2) GO TO 102
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DO 101 K=1,L1
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TI5 = CC(2,2,K)-CC(2,5,K)
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TI2 = CC(2,2,K)+CC(2,5,K)
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TI4 = CC(2,3,K)-CC(2,4,K)
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TI3 = CC(2,3,K)+CC(2,4,K)
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TR5 = CC(1,2,K)-CC(1,5,K)
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TR2 = CC(1,2,K)+CC(1,5,K)
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TR4 = CC(1,3,K)-CC(1,4,K)
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TR3 = CC(1,3,K)+CC(1,4,K)
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CH(1,K,1) = CC(1,1,K)+TR2+TR3
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CH(2,K,1) = CC(2,1,K)+TI2+TI3
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CR2 = CC(1,1,K)+TR11*TR2+TR12*TR3
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CI2 = CC(2,1,K)+TR11*TI2+TR12*TI3
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CR3 = CC(1,1,K)+TR12*TR2+TR11*TR3
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CI3 = CC(2,1,K)+TR12*TI2+TR11*TI3
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CR5 = TI11*TR5+TI12*TR4
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CI5 = TI11*TI5+TI12*TI4
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CR4 = TI12*TR5-TI11*TR4
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CI4 = TI12*TI5-TI11*TI4
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CH(1,K,2) = CR2-CI5
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CH(1,K,5) = CR2+CI5
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CH(2,K,2) = CI2+CR5
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CH(2,K,3) = CI3+CR4
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CH(1,K,3) = CR3-CI4
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CH(1,K,4) = CR3+CI4
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CH(2,K,4) = CI3-CR4
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CH(2,K,5) = CI2-CR5
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101 CONTINUE
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RETURN
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102 IF(IDO/2.LT.L1) GO TO 105
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DO 104 K=1,L1
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CDIR$ IVDEP
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DO 103 I=2,IDO,2
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TI5 = CC(I,2,K)-CC(I,5,K)
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TI2 = CC(I,2,K)+CC(I,5,K)
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TI4 = CC(I,3,K)-CC(I,4,K)
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TI3 = CC(I,3,K)+CC(I,4,K)
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TR5 = CC(I-1,2,K)-CC(I-1,5,K)
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TR2 = CC(I-1,2,K)+CC(I-1,5,K)
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TR4 = CC(I-1,3,K)-CC(I-1,4,K)
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TR3 = CC(I-1,3,K)+CC(I-1,4,K)
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CH(I-1,K,1) = CC(I-1,1,K)+TR2+TR3
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CH(I,K,1) = CC(I,1,K)+TI2+TI3
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CR2 = CC(I-1,1,K)+TR11*TR2+TR12*TR3
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CI2 = CC(I,1,K)+TR11*TI2+TR12*TI3
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CR3 = CC(I-1,1,K)+TR12*TR2+TR11*TR3
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CI3 = CC(I,1,K)+TR12*TI2+TR11*TI3
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CR5 = TI11*TR5+TI12*TR4
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CI5 = TI11*TI5+TI12*TI4
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CR4 = TI12*TR5-TI11*TR4
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CI4 = TI12*TI5-TI11*TI4
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DR3 = CR3-CI4
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DR4 = CR3+CI4
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DI3 = CI3+CR4
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DI4 = CI3-CR4
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DR5 = CR2+CI5
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DR2 = CR2-CI5
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DI5 = CI2-CR5
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DI2 = CI2+CR5
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CH(I-1,K,2) = WA1(I-1)*DR2-WA1(I)*DI2
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CH(I,K,2) = WA1(I-1)*DI2+WA1(I)*DR2
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CH(I-1,K,3) = WA2(I-1)*DR3-WA2(I)*DI3
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CH(I,K,3) = WA2(I-1)*DI3+WA2(I)*DR3
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CH(I-1,K,4) = WA3(I-1)*DR4-WA3(I)*DI4
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CH(I,K,4) = WA3(I-1)*DI4+WA3(I)*DR4
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CH(I-1,K,5) = WA4(I-1)*DR5-WA4(I)*DI5
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CH(I,K,5) = WA4(I-1)*DI5+WA4(I)*DR5
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103 CONTINUE
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104 CONTINUE
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RETURN
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105 DO 107 I=2,IDO,2
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CDIR$ IVDEP
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DO 106 K=1,L1
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TI5 = CC(I,2,K)-CC(I,5,K)
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TI2 = CC(I,2,K)+CC(I,5,K)
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TI4 = CC(I,3,K)-CC(I,4,K)
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TI3 = CC(I,3,K)+CC(I,4,K)
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TR5 = CC(I-1,2,K)-CC(I-1,5,K)
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TR2 = CC(I-1,2,K)+CC(I-1,5,K)
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TR4 = CC(I-1,3,K)-CC(I-1,4,K)
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TR3 = CC(I-1,3,K)+CC(I-1,4,K)
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CH(I-1,K,1) = CC(I-1,1,K)+TR2+TR3
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CH(I,K,1) = CC(I,1,K)+TI2+TI3
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CR2 = CC(I-1,1,K)+TR11*TR2+TR12*TR3
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CI2 = CC(I,1,K)+TR11*TI2+TR12*TI3
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CR3 = CC(I-1,1,K)+TR12*TR2+TR11*TR3
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CI3 = CC(I,1,K)+TR12*TI2+TR11*TI3
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CR5 = TI11*TR5+TI12*TR4
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CI5 = TI11*TI5+TI12*TI4
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CR4 = TI12*TR5-TI11*TR4
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CI4 = TI12*TI5-TI11*TI4
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DR3 = CR3-CI4
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DR4 = CR3+CI4
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DI3 = CI3+CR4
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DI4 = CI3-CR4
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DR5 = CR2+CI5
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DR2 = CR2-CI5
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DI5 = CI2-CR5
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DI2 = CI2+CR5
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CH(I-1,K,2) = WA1(I-1)*DR2-WA1(I)*DI2
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CH(I,K,2) = WA1(I-1)*DI2+WA1(I)*DR2
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CH(I-1,K,3) = WA2(I-1)*DR3-WA2(I)*DI3
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CH(I,K,3) = WA2(I-1)*DI3+WA2(I)*DR3
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CH(I-1,K,4) = WA3(I-1)*DR4-WA3(I)*DI4
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CH(I,K,4) = WA3(I-1)*DI4+WA3(I)*DR4
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CH(I-1,K,5) = WA4(I-1)*DR5-WA4(I)*DI5
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CH(I,K,5) = WA4(I-1)*DI5+WA4(I)*DR5
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106 CONTINUE
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107 CONTINUE
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RETURN
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END
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