Author: Kevin B. Kenny <firstname.lastname@example.org> State: Final Type: Project Vote: Done Created: 24-Nov-2006 Post-History: Tcl-Version: 8.5 Keywords: Tcl, expression, integer, square root Tk-Ticket: 1602534
This TIP proposes a new expr math function isqrt().
With the advent of large integers, Tcl supports taking the square roots of arguments that lie outside the native floating-point range of the machine. The square roots are returned as floating point numbers if possible. This behaviour is correct when floating-point calculations are intended. There are times, however, when an arbitrary-precision square root is wanted. This root cannot be obtained by evaluating entier(sqrt($n)), because sqrt($n) has already lost precision.
This TIP proposes adding a new math function, isqrt($n), that will return the integer part of the square root of $n to arbitrary precision. The argument $n must be numeric and non-negative; it may be either integer or floating-point.
Tcl Feature Request #1602534 contains a complete reference implementation for the isqrt function.
This document has been placed in the public domain.