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kanil gunewardena

Joined: 30 Mar 2012
Posts: 2
Location: USA Posted: Wed Apr 18, 2012 1:54 am    Post subject: Cot(85) Tried to paste the equation here it does not allow images. clicked on Img it does not allow to browse to where my image is saved Anyway , I entered R^1 = 1*e^(sin(u)*cot(85) ) With U[ -pi/2, 0] And V[ -pi, 0] in new file and saved as Fib.k3ds. ( a) Clicked on Parametric Tab Chose Spherical Coordinates CANNOT FIND "LOAD" option here to load my file (b) So I deleted what was in the entry box ( Examples: Bob_1) and pasted 1*e^(sin(u)*cot(85) ) Changed ranges for u & v in the boxes Hit PERFORM button Gets an error IMPLICIT EQ f(u,v,t) --> AT col 3 Synta x Error How Do I INTERPRET THIS MATH ERROR?? Can someone help me here? kanil - PS:- I cut the Error Msg from Screen Shot ,pasted in Paint , copied and tried to paste it here, but no paste option! How Do I do this in future enquires? Many Thanks . [/img]    nextstep

Joined: 06 Jan 2007
Posts: 539 Posted: Wed Apr 18, 2012 3:58 am    Post subject: Hi,
Try this formula instead : exp(sin(u)*cot(85) )
The message IMPLICIT EQ f(u,v,t) --> AT col 3 indicates that the third letter "e" in the formula isn't correct. Here is the list of all functions used in K3DSurf:

 Quote: ============================================================================= - The function string ============================================================================= The function string understood by the class is very similar to the C-syntax. Arithmetic float expressions can be created from float literals, variables or functions using the following operators in this order of precedence: () expressions in parentheses first -A unary minus A^B exponentiation (A raised to the power B) A*B A/B A%B multiplication, division and modulo A+B A-B addition and subtraction A=B AB comparison between A and B (result is either 0 or 1) A&B result is 1 if int(A) and int(B) differ from 0, else 0. A|B result is 1 if int(A) or int(B) differ from 0, else 0. Since the unary minus has higher precedence than any other operator, for example the following expression is valid: x*-y Note that the '=' comparison can be inaccurate due to floating point precision problems (eg. "sqrt(100)=10" probably returns 0, not 1). The class supports these functions: abs(A) : Absolute value of A. If A is negative, returns -A otherwise returns A. acos(A) : Arc-cosine of A. Returns the angle, measured in radians, whose cosine is A. acosh(A) : Same as acos() but for hyperbolic cosine. asin(A) : Arc-sine of A. Returns the angle, measured in radians, whose sine is A. asinh(A) : Same as asin() but for hyperbolic sine. atan(A) : Arc-tangent of (A). Returns the angle, measured in radians, whose tangent is (A). atan2(A,B): Arc-tangent of A/B. The two main differences to atan() is that it will return the right angle depending on the signs of A and B (atan() can only return values betwen -pi/2 and pi/2), and that the return value of pi/2 and -pi/2 are possible. atanh(A) : Same as atan() but for hyperbolic tangent. ceil(A) : Ceiling of A. Returns the smallest integer greater than A. Rounds up to the next higher integer. cos(A) : Cosine of A. Returns the cosine of the angle A, where A is measured in radians. cosh(A) : Same as cos() but for hyperbolic cosine. cot(A) : Cotangent of A (equivalent to 1/tan(A)). csc(A) : Cosecant of A (equivalent to 1/sin(A)). eval(...) : This a recursive call to the function to be evaluated. The number of parameters must be the same as the number of parameters taken by the function. Usually called inside if() to avoid infinite recursion. exp(A) : Exponential of A. Returns the value of e raised to the power A where e is the base of the natural logarithm, i.e. the non-repeating value approximately equal to 2.71828182846. floor(A) : Floor of A. Returns the largest integer less than A. Rounds down to the next lower integer. if(A,B,C) : If int(A) differs from 0, the return value of this function is B, else C. Only the parameter which needs to be evaluated is evaluated, the other parameter is skipped; this makes it safe to use eval() in them. int(A) : Rounds A to the closest integer. 0.5 is rounded to 1. log(A) : Natural (base e) logarithm of A. log10(A) : Base 10 logarithm of A. max(A,B) : If A>B, the result is A, else B. min(A,B) : If A1, n*eval(n-1), 1)" Note that a recursive call has some overhead, which makes it a bit slower than any other operation. It may be a good idea to avoid recursive functions in very time-critical applications. Recursion also takes some memory, so extremely deep recursions should be avoided (eg. millions of nested recursive calls). Also note that the if() function is the only place where making a recursive call is safe. In any other place it will cause an infinite recursion (which will make the program eventually run out of memory). If this is something which should be avoided, it may be a good idea to disable the eval() function completely. The eval() function can be disabled with the DISABLE_EVAL precompiler constant (see the beginning of fparser.cc).

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