Release calc version 2.10.2t30

help/root

@@ -0,0 +1,53 @@
+NAME
+    root - root of a number
+
+SYNOPSIS
+    root(x, n, [, eps])
+
+TYPES
+    x		number
+    n		positive integer
+    eps		nonzero real, defaults to epsilon()
+
+    return	real number
+
+DESCRIPTION
+    For real x and positive integer n, n being odd if x is negative,
+    root(x,n,eps) returns a multiple of eps differing from the
+    real n-th root of x (nonnegative if x is positive) by less than
+    0.75 eps, usually by less than 0.5 eps.  If the n-th root of
+    x is a multiple of eps, it will be returned exactly.
+
+    For complex x and positive integer n, or negative x with positive even
+    n, root(x, n, eps) returns a real or complex numbers whose real
+    and imaginary parts are multiples of eps differing from the real
+    and imaginary parts of the principal n-th root of x by less than
+    0.75 eps, usually by less than 0.5 eps.
+
+    For negative x and odd n, the principal n-th root of x may be
+    obtained by using power(x, 1/n, eps).
+
+EXAMPLE
+    > print root(7, 4, 1e-5), root(7, 4, 1e-10), root(7, 4, 1e-15)
+    1.62658 1.6265765617 1.626576561697786
+
+    > print root(1+3i, 3, 1e-5), root(1 + 3i, 3, 1e-10)
+    1.34241+.59361i 1.3424077452+.5936127825i
+
+    > print root(-8, 3, 1e-5), root(-8, 34, 1e-5)
+    -2 ~1.05853505050032399594+~.09807874962631613016i
+
+    > print root(1i, 100, 1e-20)
+    .99987663248166059864+.01570731731182067575i
+
+LIMITS
+    n >= 0
+    eps > 0
+
+LIBRARY
+    void rootvalue(VALUE *x, VALUE *n, VALUE *eps, VALUE *result)
+    NUMBER *qroot(NUMBER *x, NUMBER *n, NUMBER *eps)
+    COMPLEX *qroot(COMPLEX *x, NUMBER *n, NUMBER *eps)
+
+SEE ALSO
+    power