LOAD

restrictions

 The complete linked module has a size limit of 256,000 bytes. A subroutine
 can have up to 15 arguments, which can be a mixture of constants, scalars,
 vectors, matrices, character strings, and text variables. A function can
 have up to 20 arguments, which must all be REAL*8 constants or scalars. The
 appropriate arguments, which may be constants, scalars, vectors, matrices,
 character strings, or text variables, must be used. The arguments must
 agree in variable type and number.

subroutine

 PHYSICA expects to find a user written subroutine of the form:

 SUBROUTINE subname(IATYPE,ICODE,IUPDATE,IER,ARG1,ARG2,...,ARGM)
 INTEGER*4 IATYPE(15),ICODE(3,15),IUPDATE(15),IER

 If the subroutine is to loaded via the sharable image, its name must be
 one of SUB1, SUB2, ..., SUB8.  If the subroutine is to be loaded at run-
 time via the LOAD command, its name is irrelevant and when the subroutine
 is used in the CALL command, the name is not entered.  All of the numeric
 arguments, except for the integer arguments IATYPE, ICODE, IUPDATE, and
 IER, must be REAL*8. A character argument is passed as a LOGICAL*1 array.

Additional Information on:

functions

 The user written function should have the following form:

 REAL*8 FUNCTION funcname(ARG1,ARG2,...,ARGM)
 REAL*8 ARG2,ARG2,...,ARGM

 The name of the function, funcname, is irrelevant. When the function is
 used in an expression, the name that is used must be USERN. All arguments
 must be REAL*8 variables. When the function is used in an expression, you
 can use vectors or matrices as arguments, since the expression evaluator
 will process the function one element at a time. Arithmetic errors, such
 as division by zero, over/underflow, will be asynchronously trapped.

1_example

 Suppose FUNC.OBJ is some compiled function which requires two arguments
 and DISK:[DIR]LIBRARY.OLB is an object module library that is needed by
 the routine FUNC. To compile and load this routine and then use it in an
 expression:

 $FORTRAN FUNC
 LOAD FUNC,DISK:[DIR]LIBRARY/LIB
 Z=USERN(B*X,Y-C)+COS(X)

2_example

 Suppose you want to load and use a function, FUNC, which has 3 arguments:
 x1, x2, and x3, and returns the sum of x1 and x2  when x3 is within 0.5
 of sqrt(x1^2+x2^2), else it returns 0. To compile, load and test this
 function:  
               $FORTRAN FUNC
               LOAD FUNC
               X1=RAN([1:100])
               X2=RAN([1:100])
               X3=RAN([1:100])
               Y=USERN(X1,X2,X3)
               Y2=(X1+X2)*(ABS(SQRT(X1^2+X2^2)-X3)<0.5)
 and then compare Y with Y2.

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