!
!=============================================================================
module pietc
!=============================================================================
!                           R. J. Purser (jim.purser@noaa.gov) 2014
! Some of the commonly used constants (pi etc) mainly for double-precision
! subroutines.
! ms10 etc are needed to satisfy the some (eg., gnu fortran) compilers'
! more rigorous standards regarding the way "data" statements are initialized.
! Zero and the first few units are u0,u1,u2, etc., their reciprocals being,
! o2,o3 etc and their square roots, r2,r3. Reciprocal roots are or2,or3 etc.
!=============================================================================
use kinds, only: dp,dpc
implicit none
logical ,parameter:: T=.true.,F=.false. !<- for pain-relief in logical ops
real(dp),parameter:: &
     u0=0,u1=1.0_dp,mu1=-u1,u2=2.0_dp,mu2=-u2,u3=3.0_dp,mu3=-u3,u4=4.0_dp,mu4=-u4,u5=5.0_dp,mu5=-u5, &
     u6=6.0_dp,mu6=-u6,o2=u1/2.0_dp,o3=u1/3.0_dp,o4=u1/4.0_dp,o5=u1/5.0_dp,o6=u1/6.0_dp,                  &
     pi =3.1415926535897932384626433832795028841971693993751058209749e0_dp, &
     pi2=6.2831853071795864769252867665590057683943387987502116419498e0_dp, &
     pih=1.5707963267948966192313216916397514420985846996875529104874e0_dp, &
     rpi=1.7724538509055160272981674833411451827975494561223871282138e0_dp, &
! Important square-roots
     r2 =1.4142135623730950488016887242096980785696718753769480731766e0_dp, &
     r3 =1.7320508075688772935274463415058723669428052538103806280558e0_dp, &
     r5 =2.2360679774997896964091736687312762354406183596115257242708e0_dp, &
     or2=u1/r2,or3=u1/r3,or5=u1/r5,                                         &
! Golden number:
     phi=1.6180339887498948482045868343656381177203091798057628621354e0_dp, &
! Euler-Mascheroni constant:
     euler=0.57721566490153286060651209008240243104215933593992359880e0_dp, &
! Degree to radians; radians to degrees:
     dtor=pi/180.0_dp,rtod=180.0_dp/pi,                                               & 
! Sines of all main fractions of 90 degrees (down to ninths):
     s10=.173648177666930348851716626769314796000375677184069387236241e0_dp,&
     s11=.195090322016128267848284868477022240927691617751954807754502e0_dp,&
     s13=.222520933956314404288902564496794759466355568764544955311987e0_dp,&
     s15=.258819045102520762348898837624048328349068901319930513814003e0_dp,&
     s18=.309016994374947424102293417182819058860154589902881431067724e0_dp,&
     s20=.342020143325668733044099614682259580763083367514160628465048e0_dp,&
     s22=.382683432365089771728459984030398866761344562485627041433800e0_dp,&
     s26=.433883739117558120475768332848358754609990727787459876444547e0_dp,&
     s30=o2,                                                                &
     s34=.555570233019602224742830813948532874374937190754804045924153e0_dp,&
     s36=.587785252292473129168705954639072768597652437643145991072272e0_dp,&
     s39=.623489801858733530525004884004239810632274730896402105365549e0_dp,&
     s40=.642787609686539326322643409907263432907559884205681790324977e0_dp,&
     s45=or2,                                                               &
     s50=.766044443118978035202392650555416673935832457080395245854045e0_dp,&
     s51=.781831482468029808708444526674057750232334518708687528980634e0_dp,&
     s54=.809016994374947424102293417182819058860154589902881431067724e0_dp,&
     s56=.831469612302545237078788377617905756738560811987249963446124e0_dp,&
     s60=r3*o2,                                                             &
     s64=.900968867902419126236102319507445051165919162131857150053562e0_dp,&
     s68=.923879532511286756128183189396788286822416625863642486115097e0_dp,&
     s70=.939692620785908384054109277324731469936208134264464633090286e0_dp,&
     s72=.951056516295153572116439333379382143405698634125750222447305e0_dp,&
     s75=.965925826289068286749743199728897367633904839008404550402343e0_dp,&
     s77=.974927912181823607018131682993931217232785800619997437648079e0_dp,&
     s79=.980785280403230449126182236134239036973933730893336095002916e0_dp,&
     s80=.984807753012208059366743024589523013670643251719842418790025e0_dp,&
! ... and their minuses:
     ms10=-s10,ms11=-s11,ms13=-s13,ms15=-s15,ms18=-s18,ms20=-s20,ms22=-s22,&
     ms26=-s26,ms30=-s30,ms34=-s34,ms36=-s36,ms39=-s39,ms40=-s40,ms45=-s45,&
     ms50=-s50,ms51=-s51,ms54=-s54,ms56=-s56,ms60=-s60,ms64=-s64,ms68=-s68,&
     ms70=-s70,ms72=-s72,ms75=-s75,ms77=-s77,ms79=-s79,ms80=-s80

complex(dpc),parameter:: &
     c0=(u0,u0),c1=(u1,u0),mc1=-c1,ci=(u0,u1),mci=-ci,cipi=ci*pi,     &
! Main fractional rotations, as unimodualr complex numbers:
     z000=c1        ,z010=( s80,s10),z011=( s79,s11),z013=( s77,s13),&
     z015=( s75,s15),z018=( s72,s18),z020=( s70,s20),z022=( s68,s22),&
     z026=( s64,s26),z030=( s60,s30),z034=( s56,s34),z036=( s54,s36),&
     z039=( s51,s39),z040=( s50,s40),z045=( s45,s45),z050=( s40,s50),&
     z051=( s39,s51),z054=( s36,s54),z056=( s34,s56),z060=( s30,s60),&
     z064=( s26,s64),z068=( s22,s68),z070=( s20,s70),z072=( s18,s72),&
     z075=( s15,s75),z077=( s13,s77),z079=( s11,s79),z080=( s10,s80),&
     z090=ci,        z100=(ms10,s80),z101=(ms11,s79),z103=(ms13,s77),&
     z105=(ms15,s75),z108=(ms18,s72),z110=(ms20,s70),z112=(ms22,s68),&
     z116=(ms26,s64),z120=(ms30,s60),z124=(ms34,s56),z126=(ms36,s54),&
     z129=(ms39,s51),z130=(ms40,s50),z135=(ms45,s45),z140=(ms50,s40),&
     z141=(ms51,s39),z144=(ms54,s36),z146=(ms56,s34),z150=(ms60,s30),&
     z154=(ms64,s26),z158=(ms68,s22),z160=(ms70,s20),z162=(ms72,s18),&
     z165=(ms75,s15),z167=(ms77,s13),z169=(ms79,s11),z170=(ms80,s10),&
     z180=-z000,z190=-z010,z191=-z011,z193=-z013,z195=-z015,z198=-z018,&
     z200=-z020,z202=-z022,z206=-z026,z210=-z030,z214=-z034,z216=-z036,&
     z219=-z039,z220=-z040,z225=-z045,z230=-z050,z231=-z051,z234=-z054,&
     z236=-z056,z240=-z060,z244=-z064,z248=-z068,z250=-z070,z252=-z072,&
     z255=-z075,z257=-z077,z259=-z079,z260=-z080,z270=-z090,z280=-z100,&
     z281=-z101,z283=-z103,z285=-z105,z288=-z108,z290=-z110,z292=-z112,&
     z296=-z116,z300=-z120,z304=-z124,z306=-z126,z309=-z129,z310=-z130,&
     z315=-z135,z320=-z140,z321=-z141,z324=-z144,z326=-z146,z330=-z150,&
     z334=-z154,z338=-z158,z340=-z160,z342=-z162,z345=-z165,z347=-z167,&
     z349=-z169,z350=-z170
end module pietc