pwly的具体功能和用法

sunhongli666

在下是新手，哪位高手解释下ansoft11里pwly函数的功能和用法。
自己试了试，总是提示有错，请各位高手指点！
不胜感激！

duf

查看当前的help，里面有介绍的

perch88

http://www.simol.cn/thread-17753-1-1.html  
2楼

sunhongli666

谢谢两位的指点，help文件也看了，不过没大看懂！
还有个问题，请各位指点！
如图所示的定义方法是否使k等于PHI的横坐标吗？X的值和表达式处显示是0，在这里正确吗？应该怎样定义？

perch88

v11有3个参数，v12只有两个参数

v11帮助：
The following intrinsic functions are accepted in expressions:
   if (conditional_expression, true_expression, false_expression),
   pwlx (variable, form_expression, dataset_expression),
   pwly (variable, form_expression, dataset_expression),
   sign (returns sign of argument), abs, exp, pow, ln (natural logarithm),
   log (log to the base 10), lg (log to the base 2), sqrt, floor, ceil,
   round, rand (returns a random number between 0 and 1), deg, rad,
   sin, cos, tan, asin, acos, atan, atan2, sinh, cosh, tanh.

Dataset expressions are expressions of the form:
   dset((x0, y0), ..., (xn, yn))
These expressions may be used as the third parameter to pwlx and pwly
functions, and may also be assigned to variables, in which case the
variable may be used as the third parameter to pwlx and pwly functions.

Piecewise linear functions accept a form_expression as their second
parameter, which is either:  bounded, constant, periodic, linear, or an
expression that evaluates to a number 1 through 4 (1 = bounded,
2 = constant, 3 = periodic, 4 = linear).  The pwlx function interpolates
along the x axis and returns a corresponding y value.  The pwly function
interpolates along the y axis and returns a corresponding x value.

All trigonometric functions expect their arguments to be in degrees,
and inverse trigonometric functions' return values are in degrees.
Note that "pi" is a built-in constant, and may not be reassigned.
Intrinsic function names are reserved, and may not be used as variables.

k等于PHI的横坐标
--不是这样的
--你的这个pwlx(X,linear,PHI)的意思是，PHI是个二维表格，有两列
--pwlx(X,linear,PHI)的值是查PHI这个二维表格得来的，具体的值是0，那是因为X=0
--你肯定是在PHI里面定义了0  0这样的行

sunhongli666

5# perch88 谢谢您！我还有个问题不太懂，请您帮助解决解决。
1、上边图里的X值是我自己定义的为0，因为在我定义k的那个表达式的时候，如果不定义x，直接输“X”，会提示错误： 没有定义X这个变量，所以我就随便给了X一个值，觉得这样可能不对，但是也不知道这样处理X；
2、还有就是您说我所定义的是返回二维表格里的值，那么怎样确定返回的是横坐标还是纵坐标。
我要定义的是一个边界上的表达式，如图所示。
请这位仁兄看看，有空儿的情况下，帮忙解决下，在这里先感谢了！！！