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+====== "posy" Polynomial with non-integer powers ======
+===== Syntax =====
+  posy  c1,p1 c2,p2 ...
+  posy  c1,p1 c2,p2 ... args
+===== Purpose =====
+Defines a transfer function by a one dimensional ``posynomial'', like
+a polynomial, except that the powers are arbitrary, and usually non-integer.
+===== Comments =====
+There is no corresponding capability in any SPICE that I know of.
+For capacitors, this function defines //charge// as a function of
+voltage.  For inductors, it defines //flux// as a function of
+current.
+For fixed sources, it defines voltage or current as a function of
+time.
+Normal use of this function required positive input (voltage or
+current).  The result is zero if the input is negative.  Raising a
+negative number to a non-integer power would produce a complex result,
+which implies a non-causal result, which cannot be represented in a
+traditional transient analysis.
+The transfer function is defined by:
+<code>
+if (in >= 0){
+  out = (c1*in^p1) + (c2*in^p2) + ....
+}else{
+  out = 0.
+}
+</code>
+===== Parameters =====
+|min   |Minimum output value (clipping).  (Default  = -infinity)  |
+|max   |Maximum output value (clipping).  (Default  = infinity)  |
+|abs   |Absolute value, truth value.  (Default = false).  If set to true, the result will be always positive.  |
+|odd   |Make odd function, truth value.  (Default = false).  If set to true, negative values of x will be evaluated as out = -f(-x), giving odd symmetry.  |
+|even  |Make even function, truth value.  (Default = false).  If set to true, negative values of x will be evaluated as out = f(-x), giving even symmetry.  |
+===== Example =====
+  E1 (2 0 1 0) posy(1 .5)
+The output of E1 is the square root of its input.