Add some tentative fixes related to the usage of NSString and other functions

Author: pedrovgs

Sources/Matft/library/lapack.swift

@@ -139,9 +139,11 @@ internal func wrap_lapack_inv<T: MfStorable>(_ rowcolnum: Int, _ srcdstptr: Unsa
 /// - Throws: An error of type `MfError.LinAlgError.singularMatrix`
 @inline(__always)
 internal func wrap_lapack_eigen<T: MfStorable>(_ rowcolnum: Int, _ srcptr: UnsafeMutablePointer<T>, _ dstLVecRePtr: UnsafeMutablePointer<T>, _ dstLVecImPtr: UnsafeMutablePointer<T>, _ dstRVecRePtr: UnsafeMutablePointer<T>, _ dstRVecImPtr: UnsafeMutablePointer<T>, _ dstValRePtr: UnsafeMutablePointer<T>, _ dstValImPtr: UnsafeMutablePointer<T>, lapack_func: lapack_eigen_func<T>) throws {
-    let JOBVL = UnsafeMutablePointer(mutating: ("V" as NSString).utf8String)!
-    let JOBVR = UnsafeMutablePointer(mutating: ("V" as NSString).utf8String)!
-    
+    var jobvlStr = Array("V".utf8CString)
+    var jobvrStr = Array("V".utf8CString)
+    let JOBVL = UnsafeMutablePointer<CChar>(&jobvlStr)
+    let JOBVR = UnsafeMutablePointer<CChar>(&jobvrStr)
+
     var N = __CLPK_integer(rowcolnum)
 
     var LDA = __CLPK_integer(rowcolnum)
@@ -322,8 +324,9 @@ internal func wrap_lapack_eigen<T: MfStorable>(_ rowcolnum: Int, _ srcptr: Unsaf
 /// - Throws: An error of type `MfError.LinAlgError.singularMatrix`
 @inline(__always)
 internal func wrap_lapack_svd<T: MfStorable>(_ rownum: Int, _ colnum: Int, _ srcptr: UnsafeMutablePointer<T>, _ vptr: UnsafeMutablePointer<T>, _ sptr: UnsafeMutablePointer<T>, _ rtptr: UnsafeMutablePointer<T>, _ full_matrices: Bool, lapack_func: lapack_svd_func<T>) throws{
-    let JOBZ: UnsafeMutablePointer<Int8>
-    
+    var jobzStr = full_matrices ? Array("A".utf8CString) : Array("S".utf8CString)
+    let JOBZ = UnsafeMutablePointer<CChar>(&jobzStr)
+
     var M = __CLPK_integer(rownum)
     var N = __CLPK_integer(colnum)
 
@@ -342,14 +345,12 @@ internal func wrap_lapack_svd<T: MfStorable>(_ rownum: Int, _ colnum: Int, _ src
 
 
     if full_matrices{
-        JOBZ = UnsafeMutablePointer(mutating: ("A" as NSString).utf8String)!
         LDVT = __CLPK_integer(colnum)
 
         ucol = rownum
         vtrow = colnum
     }
     else{
-        JOBZ = UnsafeMutablePointer(mutating: ("S" as NSString).utf8String)!
         LDVT = __CLPK_integer(snum)
 
         ucol = snum
@@ -872,8 +873,10 @@ internal func wrap_lapack_inv<T: MfStorable>(_ rowcolnum: Int, _ srcdstptr: Unsa
 
 @inline(__always)
 internal func wrap_lapack_eigen<T: MfStorable>(_ rowcolnum: Int, _ srcptr: UnsafeMutablePointer<T>, _ dstLVecRePtr: UnsafeMutablePointer<T>, _ dstLVecImPtr: UnsafeMutablePointer<T>, _ dstRVecRePtr: UnsafeMutablePointer<T>, _ dstRVecImPtr: UnsafeMutablePointer<T>, _ dstValRePtr: UnsafeMutablePointer<T>, _ dstValImPtr: UnsafeMutablePointer<T>, lapack_func: lapack_eigen_func<T>) throws {
-    let JOBVL = UnsafeMutablePointer(mutating: ("V" as NSString).utf8String)!
-    let JOBVR = UnsafeMutablePointer(mutating: ("V" as NSString).utf8String)!
+    var jobvlStr = Array("V".utf8CString)
+    var jobvrStr = Array("V".utf8CString)
+    let JOBVL = UnsafeMutablePointer<CChar>(&jobvlStr)
+    let JOBVR = UnsafeMutablePointer<CChar>(&jobvrStr)
 
     var N = __CLPK_integer(rowcolnum)
     var LDA = __CLPK_integer(rowcolnum)
@@ -951,7 +954,8 @@ internal func wrap_lapack_eigen<T: MfStorable>(_ rowcolnum: Int, _ srcptr: Unsaf
 
 @inline(__always)
 internal func wrap_lapack_svd<T: MfStorable>(_ rownum: Int, _ colnum: Int, _ srcptr: UnsafeMutablePointer<T>, _ vptr: UnsafeMutablePointer<T>, _ sptr: UnsafeMutablePointer<T>, _ rtptr: UnsafeMutablePointer<T>, _ full_matrices: Bool, lapack_func: lapack_svd_func<T>) throws {
-    let JOBZ: UnsafeMutablePointer<Int8>
+    var jobzStr = full_matrices ? Array("A".utf8CString) : Array("S".utf8CString)
+    let JOBZ = UnsafeMutablePointer<CChar>(&jobzStr)
     var M = __CLPK_integer(rownum)
     var N = __CLPK_integer(colnum)
     let ucol: Int, vtrow: Int
@@ -964,13 +968,11 @@ internal func wrap_lapack_svd<T: MfStorable>(_ rownum: Int, _ colnum: Int, _ src
     var LDVT: __CLPK_integer
 
     if full_matrices {
-        JOBZ = UnsafeMutablePointer(mutating: ("A" as NSString).utf8String)!
         LDVT = __CLPK_integer(colnum)
         ucol = rownum
         vtrow = colnum
     }
     else {
-        JOBZ = UnsafeMutablePointer(mutating: ("S" as NSString).utf8String)!
         LDVT = __CLPK_integer(snum)
         ucol = snum
         vtrow = snum