linspace* fx

docs/lqn.md

@@ -620,6 +620,21 @@
  ;   Source file: /data/x/lqn/src/io.lisp
 ```
 
+#### LQN:LINSPACE\*
+
+```
+ ; LQN:LINSPACE*
+ ;   [symbol]
+ ; 
+ ; LINSPACE* names a compiled function:
+ ;   Lambda-list: (N &OPTIONAL (A 0.0) (B 1.0) (END T))
+ ;   Derived type: (FUNCTION (FIXNUM &OPTIONAL REAL REAL BOOLEAN)
+ ;                  (VALUES (AND (VECTOR T) (NOT SIMPLE-ARRAY)) &OPTIONAL))
+ ;   Documentation:
+ ;     n floats from a to b.
+ ;   Source file: /data/x/lqn/src/qry-utils.lisp
+```
+
 #### LQN:LPAD
 
 ```

src/basic-utils.lisp

@@ -9,7 +9,7 @@
 (defvar *fxns* '(:err :wrn :nope :noop :lst :lit :qt :hld :ghv :pnum :inum :cnt :λ
                  :fmt :out :jsnstr
                  :fn :fi :ctx  :par :itr :compct :?? :@@ :@* :smth? :ind* :sel* :seq* :apply* :join
-                 :new* :new$ :cat* :cat$ :head* :tail* :size? :range* :pop* :psh*
+                 :new* :new$ :cat* :cat$ :head* :tail* :size? :range* :linspace* :pop* :psh*
                  :flatn* :flatall* :flatn$ :uniq
                  :pref? :suf? :sub? :subx? :ipref? :isuf? :isub? :isubx? :lpad :rpad :nstr
                  :sup :sdwn :mkstr :repl :strcat :splt

src/packages.lisp

@@ -5,8 +5,9 @@
     #:qry #:qryd #:jsnqryf #:qryl #:proc-qry
     #:jsnloads #:jsnloadf #:jsnout #:ldnout #:fmt #:out #:jsnstr #:@* #:@@ #:??
     #:some? #:none? #:all? #:empty? #:size? #:is?
-    #:path? #:subdir #:subfiles #:ls #:dir? #:file? #:cwd #:now #:cmd #:some? #:all? #:none? #:cd
-    #:new* #:new$ #:cat$ #:cat* #:head* #:tail* #:apply* #:range* #:psh* #:pop*
+    #:path? #:subdir #:subfiles #:ls #:dir? #:file? #:cwd #:now #:cmd
+    #:some? #:all? #:none? #:cd
+    #:new* #:new$ #:cat$ #:cat* #:head* #:tail* #:apply* #:range* #:linspace* #:psh* #:pop*
     #:flatn* #:compct #:flatall* #:flatn$ #:uniq
     #:pnum #:inum #:cnt
     #:noop #:kv? #:kw? #:ssym? #:msym? #:trim #:sym!

src/qry-utils.lisp

@@ -74,6 +74,16 @@ match. If b is an expression, a is compared to the evaluated value of b."
     (make-array (length init) :initial-contents init
                 :adjustable t :fill-pointer t)))
 
+(defun linspace* (n &optional (a 0.0) (b 1.0) (end t))
+  (declare #.*opt* (fixnum n) (real a b) (boolean end)) "n floats from a to b."
+  (let ((res (make-array n :initial-element 0.0 :adjustable t
+                           :fill-pointer t :element-type 'float)))
+    (if (> n 1) (loop with ban = (/ (- b a) (if end (1- n) n))
+                      for i of-type fixnum from 0 below n
+                      do (setf (aref res i) (coerce (+ a (* i ban)) 'float)))
+                (setf (aref res 0) a))
+    res))
+
 ; TODO: fx to convert non-fill-ptr array to fpa?
 (defmacro psh* (a o) (declare (symbol a)) "extend a with o. return a. destructive."
   `(progn (vector-push-extend ,o ,a) ,a))