! File: fft27a.i90
! Public domain 2004 James Van Buskirk
subroutine fft27a(h)
! 368 adds, 152 muls
   complex(wp), intent(inout) :: h(0:26)
   real(wp) xr1, xi1, xr2, xi2, xr3, xi3, xr4, xi4, xr5, xi5
   real(wp) xr6, xi6, xr7, xi7, xr8, xi8, xr9, xi9, xra, xia
   real(wp) xrb, xib, xrc, xic, xrd, xid, xre, xie
   real(wp) yr1, yi1, yr2, yi2, yr3, yi3, yr4, yi4, yr5, yi5
   real(wp) yr6, yi6, yr7, yi7, yr8, yi8, yr9, yi9, yra, yia
   real(wp) yrb, yib, yrc, yic, yrd, yid
   real(wp) xr3a, xi3a, xr3_a, xi3_a
   real(wp) xr94, xi94, xr9_4, xi9_4
   real(wp) xr67, xi67, xr6_7, xi6_7
   real(wp) xr58, xi58, xr5_8, xi5_8
   real(wp) yr29, yi29, yr2_9, yi2_9
   real(wp) yr83, yi83, yr8_3, yi8_3
   real(wp) yr56, yi56, yr5_6, yi5_6
   real(wp) yr47, yi47, yr4_7, yi4_7
   real(wp) xr396a47, xi396a47, xr258, xi258, pr142, pi142
   real(wp) pr0, pi0, pr1, pi1, pr4, pi4, pr2, pi2, pr3, pi3
   real(wp) pr7, pi7, pr586, pi586
   real(wp) pr5, pi5, pr8, pi8, pr6, pi6
   real(wp) yr285936, yi285936, yr147, yi147, qr142, qi142
   real(wp) qr0, qi0, qr1, qi1, qr4, qi4, qr2, qi2, qr3, qi3
   real(wp) qr7, qi7, qr586, qi586
   real(wp) qr5, qi5, qr8, qi8, qr6, qi6
   real(wp) xrbcd, xibcd, xr1e, xi1e, xr1_e, xi1_e
   real(wp) sr1e, si1e, sr1, si1, sre, sie
   real(wp) ur258, ui258, ur2, ui2, ur5, ui5, ur8, ui8
   real(wp) ur3, ui3, ur4, ui4, ur6, ui6
   real(wp) ur7, ui7, ur9, ui9, ura, uia
   real(wp) srbcd, sibcd, urb, uib, urc, uic, ur_d, ui_d
   real(wp) srb, sib, src, sic, srd, sid
   real(wp) sr2, si2, sr3, si3, sr4, si4
   real(wp) sr5, si5, sr6, si6, sr7, si7
   real(wp) sr8, si8, sr9, si9, sra, sia
   real(wp) yrabc, yiabc
   real(wp) trd, tid
   real(wp) vr147, vi147, vr1, vi1, vr4, vi4, vr7, vi7
   real(wp) vr2, vi2, vr3, vi3, vr5, vi5
   real(wp) vr6, vi6, vr8, vi8, vr9, vi9
   real(wp) trabc, tiabc, vrb, vib, vrc, vic, vr_a, vi_a
   real(wp) tra, tia, trb, tib, trc, tic
   real(wp) tr1, ti1, tr2, ti2, tr3, ti3
   real(wp)  tr4, ti4, tr5, ti5, tr6, ti6
   real(wp) tr7, ti7, tr8, ti8, tr9, ti9
   real(wp), parameter :: half =  0.50000000000000000000000000000000000_wp
   real(wp), parameter :: dc1 =  -0.57642814744875870894356548634397085_wp
   real(wp), parameter :: dc2 =  0.37534932178512936778775671736975588_wp
   real(wp), parameter :: dc3 =  -0.16990116397762442780123070654139485_wp
   real(wp), parameter :: dc4 =  1.5592192877587242400451696503448437_wp
   real(wp), parameter :: dc5 =  -0.35375451960733467391558398434425275_wp
   real(wp), parameter :: dc6 =  1.3055319888412227506469061880579815_wp
   real(wp), parameter :: dc7 =  0.23463617422271728795511750546719294_wp
   real(wp), parameter :: dc8 =  1.4944842775136313798912828514190466_wp
   real(wp), parameter :: dc9 =  3.4444779501914135581371229812285541E-0002_wp
   real(wp), parameter :: dc10 =  1.6248417289466432889811189425899489_wp
   real(wp), parameter :: dc11 =  0.52938463881364237539017828848881944_wp
   real(wp), parameter :: dc12 =  0.73046346447727171654598705746303349_wp
   real(wp), parameter :: dc13 =  -0.93969262078590838405410927732473143_wp
   real(wp), parameter :: dc14 =  1.7057370639048864192565019278801480_wp
   real(wp), parameter :: dc15 =  1.1133407984528387329058259040940457_wp
   real(wp), parameter :: dc16 =  0.76604444311897803520239265055541608_wp
   real(wp), parameter :: dc17 =  -0.55667039922641936645291295204702315_wp
   real(wp), parameter :: dc18 =  -0.29619813272602384317533801189305085_wp
   real(wp), parameter :: r3 =  0.86602540378443864676372317075293616_wp
   real(wp), parameter :: ds1 =  -0.13661598058179370950469763186607038_wp
   real(wp), parameter :: ds2 =  -1.5837233190535240903375586753824913_wp
   real(wp), parameter :: ds3 =  -0.56750940943792405345618398900616916_wp
   real(wp), parameter :: ds4 =  -0.46679961156758019097844394968917870_wp
   real(wp), parameter :: ds5 =  -0.47517478382056093164794148757277248_wp
   real(wp), parameter :: ds6 =  -0.97193255465116944918491955594364809_wp
   real(wp), parameter :: ds7 =  -0.54394779259379259520491653846635096_wp
   real(wp), parameter :: ds8 =  0.64465759046413645768265657778334321_wp
   real(wp), parameter :: ds9 =  -0.59139402473021103647230321846204473_wp
   real(wp), parameter :: ds10 =  9.4636253899602518935325150091169794E-0002_wp
   real(wp), parameter :: ds11 =  -0.26586695828869437347734159549943322_wp
   real(wp), parameter :: ds12 =  1.4544723413466234263649147117491282_wp
   real(wp), parameter :: ds13 =  -0.98480775301220805936674302458952306_wp
   real(wp), parameter :: ds14 =  1.6275953626987473856893864344967864_wp
   real(wp), parameter :: ds15 =  1.3268278963378767924108426392717827_wp
   real(wp), parameter :: ds16 =  0.34202014332566873304409961468225881_wp
   real(wp), parameter :: ds17 =  -0.81379768134937369284469321724839351_wp
   real(wp), parameter :: ds18 =  0.15038373318043529663927189761250216_wp
   real(wp), parameter :: cc1 =  -1.2931284138572722560360728515498211_wp
   real(wp), parameter :: cc2 =  2.8793852415718167681082185546494632_wp
   real(wp), parameter :: cc3 =  -1.6880592574919707136031902007405558_wp
   real(wp), parameter :: cc4 =  0.84402962874598535680159510037027790_wp
   real(wp), parameter :: cs1 =  -0.39493084363469845756711734919073458_wp
   real(wp), parameter :: cs2 =  0.18479253090409537270135204757220363_wp
   real(wp), parameter :: cs3 =  -0.53208888623795607040478530111083331_wp

   xr1 = real(h(0))
   xi1 = aimag(h(0))
   xr2 = real(h(1))+real(h(26))
   xi2 = aimag(h(1))+aimag(h(26))
   xr3 = real(h(4))+real(h(23))
   xi3 = aimag(h(4))+aimag(h(23))
   xr4 = real(h(7))+real(h(20))
   xi4 = aimag(h(7))+aimag(h(20))
   xr5 = real(h(10))+real(h(17))
   xi5 = aimag(h(10))+aimag(h(17))
   xr6 = real(h(13))+real(h(14))
   xi6 = aimag(h(13))+aimag(h(14))
   xr7 = real(h(16))+real(h(11))
   xi7 = aimag(h(16))+aimag(h(11))
   xr8 = real(h(19))+real(h(8))
   xi8 = aimag(h(19))+aimag(h(8))
   xr9 = real(h(22))+real(h(5))
   xi9 = aimag(h(22))+aimag(h(5))
   xra = real(h(25))+real(h(2))
   xia = aimag(h(25))+aimag(h(2))
   xrb = real(h(3))+real(h(24))
   xib = aimag(h(3))+aimag(h(24))
   xrc = real(h(12))+real(h(15))
   xic = aimag(h(12))+aimag(h(15))
   xrd = real(h(21))+real(h(6))
   xid = aimag(h(21))+aimag(h(6))
   xre = real(h(9))+real(h(18))
   xie = aimag(h(9))+aimag(h(18))
   yr1 = real(h(1))-real(h(26))
   yi1 = aimag(h(1))-aimag(h(26))
   yr2 = real(h(4))-real(h(23))
   yi2 = aimag(h(4))-aimag(h(23))
   yr3 = real(h(7))-real(h(20))
   yi3 = aimag(h(7))-aimag(h(20))
   yr4 = real(h(10))-real(h(17))
   yi4 = aimag(h(10))-aimag(h(17))
   yr5 = real(h(13))-real(h(14))
   yi5 = aimag(h(13))-aimag(h(14))
   yr6 = real(h(16))-real(h(11))
   yi6 = aimag(h(16))-aimag(h(11))
   yr7 = real(h(19))-real(h(8))
   yi7 = aimag(h(19))-aimag(h(8))
   yr8 = real(h(22))-real(h(5))
   yi8 = aimag(h(22))-aimag(h(5))
   yr9 = real(h(25))-real(h(2))
   yi9 = aimag(h(25))-aimag(h(2))
   yra = real(h(3))-real(h(24))
   yia = aimag(h(3))-aimag(h(24))
   yrb = real(h(12))-real(h(15))
   yib = aimag(h(12))-aimag(h(15))
   yrc = real(h(21))-real(h(6))
   yic = aimag(h(21))-aimag(h(6))
   yrd = real(h(9))-real(h(18))
   yid = aimag(h(9))-aimag(h(18))
   xr3a = xr3+xra
   xi3a = xi3+xia
   xr3_a = xr3-xra
   xi3_a = xi3-xia
   xr94 = xr9+xr4
   xi94 = xi9+xi4
   xr9_4 = xr9-xr4
   xi9_4 = xi9-xi4
   xr67 = xr6+xr7
   xi67 = xi6+xi7
   xr6_7 = xr6-xr7
   xi6_7 = xi6-xi7
   xr58 = xr5+xr8
   xi58 = xi5+xi8
   xr5_8 = xr5-xr8
   xi5_8 = xi5-xi8
   xr396a47 = xr3a+xr94+xr67
   xi396a47 = xi3a+xi94+xi67
   xr258 = xr2+xr58
   xi258 = xi2+xi58
   pr142 = cc3*xr2+cc1*xr396a47+cc4*xr58
   pi142 = cc3*xi2+cc1*xi396a47+cc4*xi58
   pr0 = xr258+xr396a47
   pi0 = xi258+xi396a47
   pr1 = pr142+xr94+cc2*xr67
   pi1 = pi142+xi94+cc2*xi67
   pr4 = pr142+cc2*xr3a+xr67
   pi4 = pi142+cc2*xi3a+xi67
   pr2 = pr142+xr3a+cc2*xr94
   pi2 = pi142+xi3a+cc2*xi94
   pr3 = xr258-half*xr396a47
   pi3 = xi258-half*xi396a47
   pr7 = xr3_a+xr9_4+xr6_7
   pi7 = xi3_a+xi9_4+xi6_7
   pr586 = cs1*pr7+cs3*xr5_8
   pi586 = cs1*pi7+cs3*xi5_8
   pr5 = pr586+xr9_4+cs2*xr6_7
   pi5 = pi586+xi9_4+cs2*xi6_7
   pr8 = pr586+cs2*xr3_a+xr6_7
   pi8 = pi586+cs2*xi3_a+xi6_7
   pr6 = pr586+xr3_a+cs2*xr9_4
   pi6 = pi586+xi3_a+cs2*xi9_4
   xrbcd = xrb+xrc+xrd
   xibcd = xib+xic+xid
   xr1e = xr1+xre
   xi1e = xi1+xie
   xr1_e = xr1-half*xre
   xi1_e = xi1-half*xie
   sr1e = xr1e+xrbcd
   si1e = xi1e+xibcd
   sr1 = sr1e+pr0
   si1 = si1e+pi0
   sre = sr1e-half*pr0
   sie = si1e-half*pi0
   ur258 = dc13*xrbcd+xr1_e
   ui258 = dc13*xibcd+xi1_e
   ur2 = ur258+dc14*xrb+dc15*xrd
   ui2 = ui258+dc14*xib+dc15*xid
   ur5 = ur258+dc15*xrc+dc14*xrd
   ui5 = ui258+dc15*xic+dc14*xid
   ur8 = ur258+dc15*xrb+dc14*xrc
   ui8 = ui258+dc15*xib+dc14*xic
   ur3 = dc1*pr1+dc2*pr5
   ui3 = dc1*pi1+dc2*pi5
   ur4 = dc3*pr1+dc4*pr5
   ui4 = dc3*pi1+dc4*pi5
   ur6 = dc5*pr4+dc6*pr8
   ui6 = dc5*pi4+dc6*pi8
   ur7 = dc7*pr4+dc8*pr8
   ui7 = dc7*pi4+dc8*pi8
   ur9 = dc9*pr2+dc10*pr6
   ui9 = dc9*pi2+dc10*pi6
   ura = dc11*pr2+dc12*pr6
   uia = dc11*pi2+dc12*pi6
   srbcd = xr1e-half*xrbcd
   sibcd = xi1e-half*xibcd
   urb = dc16*pr3+dc17*pr7
   uib = dc16*pi3+dc17*pi7
   urc = dc13*pr3+dc18*pr7
   uic = dc13*pi3+dc18*pi7
   ur_d = urb+urc
   ui_d = uib+uic
   srb = srbcd+urb
   sib = sibcd+uib
   src = srbcd+urc
   sic = sibcd+uic
   srd = srbcd-ur_d
   sid = sibcd-ui_d
   sr2 = ur2+ur3
   si2 = ui2+ui3
   sr3 = ur2-ur3+ur4
   si3 = ui2-ui3+ui4
   sr4 = ur2-ur4
   si4 = ui2-ui4
   sr5 = ur5+ur6
   si5 = ui5+ui6
   sr6 = ur5-ur6+ur7
   si6 = ui5-ui6+ui7
   sr7 = ur5-ur7
   si7 = ui5-ui7
   sr8 = ur8+ur9
   si8 = ui8+ui9
   sr9 = ur8-ur9+ura
   si9 = ui8-ui9+uia
   sra = ur8-ura
   sia = ui8-uia

   yr29 = yr2+yr9
   yi29 = yi2+yi9
   yr2_9 = yr2-yr9
   yi2_9 = yi2-yi9
   yr83 = yr8+yr3
   yi83 = yi8+yi3
   yr8_3 = yr8-yr3
   yi8_3 = yi8-yi3
   yr56 = yr5+yr6
   yi56 = yi5+yi6
   yr5_6 = yr5-yr6
   yi5_6 = yi5-yi6
   yr47 = yr4+yr7
   yi47 = yi4+yi7
   yr4_7 = yr4-yr7
   yi4_7 = yi4-yi7
   yr285936 = yr29+yr83+yr56
   yi285936 = yi29+yi83+yi56
   yr147 = yr1+yr47
   yi147 = yi1+yi47
   qr142 = cc3*yr1+cc1*yr285936+cc4*yr47
   qi142 = cc3*yi1+cc1*yi285936+cc4*yi47
   qr0 = yr147+yr285936
   qi0 = yi147+yi285936
   qr1 = qr142+yr83+cc2*yr56
   qi1 = qi142+yi83+cc2*yi56
   qr4 = qr142+cc2*yr29+yr56
   qi4 = qi142+cc2*yi29+yi56
   qr2 = qr142+yr29+cc2*yr83
   qi2 = qi142+yi29+cc2*yi83
   qr3 = yr147-half*yr285936
   qi3 = yi147-half*yi285936
   qr7 = yr2_9+yr8_3+yr5_6
   qi7 = yi2_9+yi8_3+yi5_6
   qr586 = cs1*qr7+cs3*yr4_7
   qi586 = cs1*qi7+cs3*yi4_7
   qr5 = qr586+yr8_3+cs2*yr5_6
   qi5 = qi586+yi8_3+cs2*yi5_6
   qr8 = qr586+cs2*yr2_9+yr5_6
   qi8 = qi586+cs2*yi2_9+yi5_6
   qr6 = qr586+yr2_9+cs2*yr8_3
   qi6 = qi586+yi2_9+cs2*yi8_3
   yrabc = yra+yrb+yrc
   yiabc = yia+yib+yic
   trd = r3*qr0
   tid = r3*qi0
   vr147 = ds13*yrabc+r3*yrd
   vi147 = ds13*yiabc+r3*yid
   vr1 = vr147+ds14*yra+ds15*yrb
   vi1 = vi147+ds14*yia+ds15*yib
   vr4 = vr147+ds15*yra+ds14*yrc
   vi4 = vi147+ds15*yia+ds14*yic
   vr7 = vr147+ds14*yrb+ds15*yrc
   vi7 = vi147+ds14*yib+ds15*yic
   vr2 = ds1*qr1+ds2*qr5
   vi2 = ds1*qi1+ds2*qi5
   vr3 = ds3*qr1+ds4*qr5
   vi3 = ds3*qi1+ds4*qi5
   vr5 = ds5*qr4+ds6*qr8
   vi5 = ds5*qi4+ds6*qi8
   vr6 = ds7*qr4+ds8*qr8
   vi6 = ds7*qi4+ds8*qi8
   vr8 = ds9*qr2+ds10*qr6
   vi8 = ds9*qi2+ds10*qi6
   vr9 = ds11*qr2+ds12*qr6
   vi9 = ds11*qi2+ds12*qi6
   trabc = r3*yrabc
   tiabc = r3*yiabc
   vrb = ds16*qr3+ds17*qr7
   vib = ds16*qi3+ds17*qi7
   vrc = ds13*qr3+ds18*qr7
   vic = ds13*qi3+ds18*qi7
   vr_a = vrb+vrc
   vi_a = vib+vic
   tra = trabc-vr_a
   tia = tiabc-vi_a
   trb = trabc+vrb
   tib = tiabc+vib
   trc = trabc+vrc
   tic = tiabc+vic
   tr1 = vr1+vr2
   ti1 = vi1+vi2
   tr2 = vr1-vr2+vr3
   ti2 = vi1-vi2+vi3
   tr3 = vr1-vr3
   ti3 = vi1-vi3
   tr4 = vr4+vr5
   ti4 = vi4+vi5
   tr5 = vr4-vr5+vr6
   ti5 = vi4-vi5+vi6
   tr6 = vr4-vr6
   ti6 = vi4-vi6
   tr7 = vr7+vr8
   ti7 = vi7+vi8
   tr8 = vr7-vr8+vr9
   ti8 = vi7-vi8+vi9
   tr9 = vr7-vr9
   ti9 = vi7-vi9

   h(0) = cmplx(sr1,si1,wp)
   h(1) = cmplx(sr2+ti1,si2-tr1,wp)
   h(2) = cmplx(sra-ti9,sia+tr9,wp)
   h(3) = cmplx(srb+tia,sib-tra,wp)
   h(4) = cmplx(sr5+ti4,si5-tr4,wp)
   h(5) = cmplx(sr7-ti6,si7+tr6,wp)
   h(6) = cmplx(srd-tic,sid+trc,wp)
   h(7) = cmplx(sr8+ti7,si8-tr7,wp)
   h(8) = cmplx(sr4-ti3,si4+tr3,wp)
   h(9) = cmplx(sre+tid,sie-trd,wp)
   h(10) = cmplx(sr3+ti2,si3-tr2,wp)
   h(11) = cmplx(sr9-ti8,si9+tr8,wp)
   h(12) = cmplx(src+tib,sic-trb,wp)
   h(13) = cmplx(sr6+ti5,si6-tr5,wp)
   h(14) = cmplx(sr6-ti5,si6+tr5,wp)
   h(15) = cmplx(src-tib,sic+trb,wp)
   h(16) = cmplx(sr9+ti8,si9-tr8,wp)
   h(17) = cmplx(sr3-ti2,si3+tr2,wp)
   h(18) = cmplx(sre-tid,sie+trd,wp)
   h(19) = cmplx(sr4+ti3,si4-tr3,wp)
   h(20) = cmplx(sr8-ti7,si8+tr7,wp)
   h(21) = cmplx(srd+tic,sid-trc,wp)
   h(22) = cmplx(sr7+ti6,si7-tr6,wp)
   h(23) = cmplx(sr5-ti4,si5+tr4,wp)
   h(24) = cmplx(srb-tia,sib+tra,wp)
   h(25) = cmplx(sra+ti9,sia-tr9,wp)
   h(26) = cmplx(sr2-ti1,si2+tr1,wp)
end subroutine fft27a