
healpix_types
This module defines a set of parameters used by most other
HEALPix modules. Location in HEALPix directory tree:
src/f90/mod/healpix_types.F90
The parameters defined in healpix_types include

'kind' parameters, used when defining the type of a variable,
0
name 
type 
value^{1} 
definition 
I1B 
integer 
1 
number of bytes in the hardwaresupported signed integers covering the range 99 to
99 with the least margin 
I2B 
integer 
2 
same as above for the range 9999 to 9999 (ie, 4 digits) 
I4B 
integer 
4 
same as above for 9 digits 
I8B 
integer 
8 
same as above for 16 digits^{2} 
SP 
integer 
4 
number of bytes in the hardwaresupported floatingpoint
numbers covering the range 10^{30} to 10^{30} with the least margin
(hereafter single precision) 
DP 
integer 
8 
same as above for the range 10^{200} to 10^{200}
(double precision) 
SPC 
integer 
4 
number of bytes in real (or imaginary) part of single precision complex numbers 
DPC 
integer 
8 
same as above for double precision complex numbers 
LGT 
integer 
4 
number of bytes in logical variables 

 ^{1} actual value may depend on hardware or compiler
 ^{2} may not be supported by
some hardware or compiler; on those systems, the user should set the
preprocessing variable NO64BITS to 1 during compilation to demote
automatically I8B to I4B


largest accessible numbers,
0
name 
type or kind 
value^{1} 
definition 
MAX_I1B 
integer 
127 
largest number accessible to integers of kind I1B 
MAX_I2B 
integer 
32767 
same as above for I2B integers 
MAX_I4B 
integer 

same as above for I4B integers 
MAX_I8B 
I8B 

same as above for I4B integers 
MAX_SP 
SP 

same as above for SP floatingpoint 
MAX_DP 
DP 

same as above for DP floatingpoint 

 ^{1} actual value may depend on hardware or compiler


mathematical definitions,
0
name 
kind 
value 
definition 
QUARTPI 
DP 


HALFPI 
DP 


PI 
DP 


TWOPI 
DP 


FOURPI 
DP 


SQRT2 
DP 


EULER 
DP 

Euler constant 
SQ4PI_INV 
DP 


TWOTHIRD 
DP 
2/3 

DEG2RAD 
DP 

Degrees to Radians conversion factor 
RAD2DEG 
DP 

Radians to Degrees conversion factor 


and HEALPix specific definitions,
0
name 
type or kind 
value 
definition 
HPX_SBADVAL 
SP 

default sentinel value given to missing
pixels in single precision data sets 
HPX_DBADVAL 
DP 

same as above for double precision data
sets 
FILENAMELEN 
integer 
1024 
default length in character of file names. 

EXAMPLE:
use healpix_types
real(kind=DP) :: dx
print*,' pi = ',PI
The value of PI, as well as all other healpix_types parameters are made known
to the code
Eric Hivon
20100618

