README.md
# f4go
[](https://travis-ci.org/Konstantin8105/f4go)
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[](https://codecov.io/gh/Konstantin8105/f4go)
[](https://raw.githubusercontent.com/Konstantin8105/f4go/master/LICENSE)
[](https://godoc.org/github.com/Konstantin8105/f4go/fortran)
[](https://codeclimate.com/github/Konstantin8105/f4go/maintainability)
# Example of use
```cmd
> # Install golang
> # Compile f4go
> go get -u github.com/Konstantin8105/f4go
> cd $GOPATH/src/github.com/Konstantin8105/f4go
> go build
> ./f4go ./testdata/blas/caxpy.f
> # Look on Go result source
> less ./testdata/blas/caxpy.go
```
# Transpiling fortran code to golang code
Present result:
```fortran
*> \brief \b CAXPY
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
* Definition:
* ===========
*
* SUBROUTINE CAXPY(N,CA,CX,INCX,CY,INCY)
*
* .. Scalar Arguments ..
* COMPLEX CA
* INTEGER INCX,INCY,N
* ..
* .. Array Arguments ..
* COMPLEX CX(*),CY(*)
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> CAXPY constant times a vector plus a vector.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> number of elements in input vector(s)
*> \endverbatim
*>
*> \param[in] CA
*> \verbatim
*> CA is COMPLEX
*> On entry, CA specifies the scalar alpha.
*> \endverbatim
*>
*> \param[in] CX
*> \verbatim
*> CX is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
*> \endverbatim
*>
*> \param[in] INCX
*> \verbatim
*> INCX is INTEGER
*> storage spacing between elements of CX
*> \endverbatim
*>
*> \param[in,out] CY
*> \verbatim
*> CY is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
*> \endverbatim
*>
*> \param[in] INCY
*> \verbatim
*> INCY is INTEGER
*> storage spacing between elements of CY
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2017
*
*> \ingroup complex_blas_level1
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> jack dongarra, linpack, 3/11/78.
*> modified 12/3/93, array(1) declarations changed to array(*)
*> \endverbatim
*>
* =====================================================================
SUBROUTINE CAXPY(N,CA,CX,INCX,CY,INCY)
*
* -- Reference BLAS level1 routine (version 3.8.0) --
* -- Reference BLAS is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2017
*
* .. Scalar Arguments ..
COMPLEX CA
INTEGER INCX,INCY,N
* ..
* .. Array Arguments ..
COMPLEX CX(*),CY(*)
* ..
*
* =====================================================================
*
* .. Local Scalars ..
INTEGER I,IX,IY
* ..
* .. External Functions ..
REAL SCABS1
EXTERNAL SCABS1
* ..
IF (N.LE.0) RETURN
IF (SCABS1(CA).EQ.0.0E+0) RETURN
IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
*
* code for both increments equal to 1
*
DO I = 1,N
CY(I) = CY(I) + CA*CX(I)
END DO
ELSE
*
* code for unequal increments or equal increments
* not equal to 1
*
IX = 1
IY = 1
IF (INCX.LT.0) IX = (-N+1)*INCX + 1
IF (INCY.LT.0) IY = (-N+1)*INCY + 1
DO I = 1,N
CY(IY) = CY(IY) + CA*CX(IX)
IX = IX + INCX
IY = IY + INCY
END DO
END IF
*
RETURN
END
```
Go code:
```golang
package main
//*> \brief \b CAXPY
//*
//* =========== DOCUMENTATION ===========
//*
//* Online html documentation available at
//* http://www.netlib.org/lapack/explore-html/
//*
//* Definition:
//* ===========
//*
//* SUBROUTINE CAXPY(N,CA,CX,INCX,CY,INCY)
//*
//* .. Scalar Arguments ..
//* COMPLEX CA
//* INTEGER INCX,INCY,N
//* ..
//* .. Array Arguments ..
//* COMPLEX CX(*),CY(*)
//* ..
//*
//*
//*> \par Purpose:
//* =============
//*>
//*> \verbatim
//*>
//*> CAXPY constant times a vector plus a vector.
//*> \endverbatim
//*
//* Arguments:
//* ==========
//*
//*> \param[in] N
//*> \verbatim
//*> N is INTEGER
//*> number of elements in input vector(s)
//*> \endverbatim
//*>
//*> \param[in] CA
//*> \verbatim
//*> CA is COMPLEX
//*> On entry, CA specifies the scalar alpha.
//*> \endverbatim
//*>
//*> \param[in] CX
//*> \verbatim
//*> CX is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
//*> \endverbatim
//*>
//*> \param[in] INCX
//*> \verbatim
//*> INCX is INTEGER
//*> storage spacing between elements of CX
//*> \endverbatim
//*>
//*> \param[in,out] CY
//*> \verbatim
//*> CY is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
//*> \endverbatim
//*>
//*> \param[in] INCY
//*> \verbatim
//*> INCY is INTEGER
//*> storage spacing between elements of CY
//*> \endverbatim
//*
//* Authors:
//* ========
//*
//*> \author Univ. of Tennessee
//*> \author Univ. of California Berkeley
//*> \author Univ. of Colorado Denver
//*> \author NAG Ltd.
//*
//*> \date November 2017
//*
//*> \ingroup complex_blas_level1
//*
//*> \par Further Details:
//* =====================
//*>
//*> \verbatim
//*>
//*> jack dongarra, linpack, 3/11/78.
//*> modified 12/3/93, array(1) declarations changed to array(*)
//*> \endverbatim
//*>
//* =====================================================================
func CAXPY(N *int, CA *complex128, CX *[]complex128, INCX *int, CY *[]complex128, INCY *int) {
I := new(int)
IX := new(int)
IY := new(int)
//*
//* -- Reference BLAS level1 routine (version 3.8.0) --
//* -- Reference BLAS is a software package provided by Univ. of Tennessee, --
//* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
//* November 2017
//*
//* .. Scalar Arguments ..
//* ..
//* .. Array Arguments ..
//* ..
//*
//* =====================================================================
//*
//* .. Local Scalars ..
//* ..
//* .. External Functions ..
//* ..
if (*(N)) <= 0 {
return
}
if (*SCABS1((CA))) == 0.0e+0 {
return
}
if (*(INCX)) == 1 && (*(INCY)) == 1 {
//*
//* code for both increments equal to 1
//*
for (*I) = 1; (*I) <= (*(N)); (*I)++ {
(*(CY))[(*I)-(1)] = (*(CY))[(*I)-(1)] + (*(CA))*(*(CX))[(*I)-(1)]
}
} else {
//*
//* code for unequal increments or equal increments
//* not equal to 1
//*
(*IX) = 1
(*IY) = 1
if (*(INCX)) < 0 {
(*IX) = (-(*(N))+1)*(*(INCX)) + 1
}
if (*(INCY)) < 0 {
(*IY) = (-(*(N))+1)*(*(INCY)) + 1
}
for (*I) = 1; (*I) <= (*(N)); (*I)++ {
(*(CY))[(*IY)-(1)] = (*(CY))[(*IY)-(1)] + (*(CA))*(*(CX))[(*IX)-(1)]
(*IX) = (*IX) + (*(INCX))
(*IY) = (*IY) + (*(INCY))
}
}
//*
return
}
```
Example of simplification Go code(comments removed for short view):
```go
package main
func CAXPY(N int, CA *complex128, CX []complex128, INCX int, CY []complex128, INCY int) {
var I int
var IX int
var IY int
if N <= 0 {
return
}
if (*SCABS1((CA))) == 0.0e+0 {
return
}
if INCX == 1 && INCY == 1 {
for I = 1; I <= N; I++ {
CY[I-1] = CY[I-1] + CA*CX[I-1]
}
} else {
IX = 1
IY = 1
if INCX < 0 {
IX = (-N+1)*INCX + 1
}
if INCY < 0 {
IY = (-N+1)*INCY + 1
}
for I = 1; I <= N; I++ {
CY[IY-1] = CY[IY-1] + CA*CX[IX-1]
IX = IX + INCX
IY = IY + INCY
}
}
return
}
```
### Notes
Fortran 77 | Golang
---------- | ------------
all arguments of function are pointers | ?
all arguments of intrisic function are pointers | ?
all internal function variables are pointers | ?
**IDENT**:
* constants
* arrays, matrixes
Operations:
* assign
* initialization
* boolean
### Fortran test sources
* [**LAPACK from lapack3.8.0**](http://netlib.org/lapack/index.html)
* [**BOSOR5**](http://shellbuckling.com/BOSOR5.php)