1Types(3) User Contributed Perl Documentation Types(3)
2
6 PDL::Types - define fundamental PDL Datatypes
7
9 use PDL::Types;
10 $pdl = ushort( 2.0, 3.0 );
12 print "The actual c type used to store ushort's is '" .
13 $pdl->type->realctype() . "'\n";
14 The actual c type used to store ushort's is 'unsigned short'
15
17 Internal module - holds all the PDL Type info. The type info can be
18 accessed easily using the "PDL::Type" object returned by the type
19 method as shown in the synopsis.
20 Skip to the end of this document to find out how to change the set of
22 types supported by PDL.
23
25 A number of functions are available for module writers to get/process
26 type information. These are used in various places (e.g. "PDL::PP",
27 "PDL::Core") to generate the appropriate type loops, etc.
28 typesrtkeys
30 Returns an array of keys of typehash sorted in order of type complexity
31 pdl> @typelist = PDL::Types::typesrtkeys;
33 pdl> print @typelist;
34 PDL_B PDL_S PDL_US PDL_L PDL_IND PDL_LL PDL_F PDL_D
35 ppdefs
37 Returns an array of pp symbols for all real types. This informs the
38 default "GenericTypes" for "pp_def" functions, making support for
39 complex types require an "opt-in".
40 pdl> print PDL::Types::ppdefs
42 B S U L N Q F D
43 ppdefs_complex
45 Returns an array of pp symbols for all complex types.
46 pdl> print PDL::Types::ppdefs_complex
48 G C
49 ppdefs_all
51 Returns an array of pp symbols for all types including complex.
52 pdl> print PDL::Types::ppdefs_all
54 B S U L N Q F D G C
55 typesynonyms
57 return type related synonym definitions to be included in pdl.h . This
58 routine must be updated to include new types as required. Mostly the
59 automatic updating should take care of the vital things.
60
62 As of 2.065, PDL supports these types:
63 SByte
65 Signed 8-bit value.
66 Byte
68 Unsigned 8-bit value.
69 Short
71 Signed 16-bit value.
72 UShort
74 Unsigned 16-bit value.
75 Long
77 Signed 32-bit value.
78 ULong
80 Unsigned 32-bit value.
81 Indx
83 Signed value, same size as a pointer on the system in use.
84 LongLong
86 Signed 64-bit value.
87 ULongLong
89 Unsigned 64-bit value.
90 Float
92 IEEE 754 <https://en.wikipedia.org/wiki/IEEE_754> single-precision
93 real floating-point value.
94 Double
96 IEEE 754 double-precision real value.
97 LDouble
99 A C99 "long double", defined as "at least as precise as a double",
100 but often more precise.
101 CFloat
103 A C99 complex single-precision floating-point value.
104 CDouble
106 A C99 complex double-precision floating-point value.
107 CLDouble
109 A C99 complex "long double" - see above for description.
110
112 This module declares one class - "PDL::Type" - objects of this class
113 are returned by the type method of an ndarray. It has several methods,
114 listed below, which provide an easy way to access type information:
115 Additionally, comparison and stringification are overloaded so that you
117 can compare and print type objects, e.g.
118 $nofloat = 1 if $pdl->type < float;
120 die "must be double" if $type != double;
121 For further examples check again the type method.
123 enum
125 Returns the number representing this datatype (see get_datatype).
126 symbol
128 Returns one of 'PDL_B', 'PDL_S', 'PDL_US', 'PDL_L', 'PDL_IND',
129 'PDL_LL', 'PDL_F' or 'PDL_D'.
130 ctype
132 Returns the macro used to represent this type in C code (eg
133 'PDL_Long').
134 ppsym
136 The letter used to represent this type in PP code (eg 'U' for
137 ushort).
138 realctype
140 The actual C type used to store this type.
141 shortctype
143 The value returned by "ctype" without the 'PDL_' prefix.
144 badvalue
146 The special numerical value used to represent bad values for this
147 type. See "badvalue" in PDL::Bad for more details.
148 isnan
150 Given a string representing a C value, will return a C expression
151 for this type that indicates whether that value is NaN (for complex
152 values, if either is NaN).
153 isfinite
155 Given a string representing a C value, will return a C expression
156 for this type that indicates whether that value is finite (for
157 complex values, if both are finite).
158 floatsuffix
160 The string appended to floating-point functions for this floating-
161 point type. Dies if called on non-floating-point type.
162 orig_badvalue
164 The default special numerical value used to represent bad values
165 for this type. (You can change the value that represents bad values
166 for each type during runtime.) See the orig_badvalue routine in
167 PDL::Bad for more details.
168 bswap
170 Returns the appropriate "bswap*" from PDL::IO::Misc for the size of
171 this type, including a no-op for types of size 1. Note this means a
172 one-line construction means you must call the return value:
173 $pdl->type->bswap->($pdl);
175
177 You can change the types that PDL knows about by editing entries in the
178 definition of the variable @types that appears close to the top of the
179 file Types.pm.PL (i.e. the file from which this module was generated).
180 Format of a type entry
182 Each entry in the @types array is a hash reference. Here is an example
183 taken from the actual code that defines the "ushort" type:
184 {
186 identifier => 'US',
187 onecharident => 'U', # only needed if different from identifier
188 pdlctype => 'PDL_Ushort',
189 realctype => 'unsigned short',
190 ppforcetype => 'ushort',
191 usenan => 0,
192 packtype => 'S*',
193 defaultbadval => 'USHRT_MAX',
194 real=>1,
195 integer=>1,
196 unsigned=>1,
197 },
198 Before we start to explain the fields please take this important
200 message on board: entries must be listed in order of increasing
201 complexity. This is critical to ensure that PDL's type conversion works
202 correctly. Basically, a less complex type will be converted to a more
203 complex type as required.
204 Fields in a type entry
206 Each type entry has a number of required and optional entry.
207 A list of all the entries:
209 • identifier
211 Required. A short sequence of upercase letters that identifies this
213 type uniquely. More than three characters is probably overkill.
214 • onecharident
216 Optional. Only required if the "identifier" has more than one
218 character. This should be a unique uppercase character that will
219 be used to reference this type in PP macro expressions of the
220 "TBSULFD" type - see "$T" in PDL::PP.
221 • pdlctype
223 Required. The "typedef"ed name that will be used to access this
225 type from C code.
226 • realctype
228 Required. The C compiler type that is used to implement this type.
230 For portability reasons this one might be platform dependent.
231 • ppforcetype
233 Required. The type name used in PP signatures to refer to this
235 type.
236 • usenan
238 Required. Flag that signals if this type has to deal with NaN
240 issues. Generally only required for floating point types.
241 • packtype
243 Required. The Perl pack type used to pack Perl values into the
245 machine representation for this type. For details see "perldoc -f
246 pack".
247 • integer
249 Required. Boolean - is this an integer type?
251 • unsigned
253 Required. Boolean - is this an unsigned type?
255 • real
257 Required. Boolean - is this a real (not complex) type?
259 • realversion
261 String - the real version of this type (e.g. cdouble -> 'D').
263 • complexversion
265 String - the complex version of this type (e.g. double -> 'C').
267 Also have a look at the entries at the top of Types.pm.PL.
269 The syntax is not written into stone yet and might change as the
271 concept matures.
272 Other things you need to do
274 You need to check modules that do I/O (generally in the IO part of the
275 directory tree). In the future we might add fields to type entries to
276 automate this. This requires changes to those IO modules first though.
277 You should also make sure that any type macros in PP files (i.e.
279 "$TBSULFD...") are updated to reflect the new type. PDL::PP::Dump has a
280 mode to check for type macros requiring updating. Do something like
281 find . -name \*.pd -exec perl -Mblib=. -M'PDL::PP::Dump=typecheck' {} \;
283 from the PDL root directory after updating Types.pm.PL to check for
285 such places.
286perl v5.36.0 2022-07-22 Types(3)