NAG Fortran Compiler, Release 7.2: Fortran 95 Intrinsic Procedures

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8.4 Fortran 95 Intrinsic Procedures

This section provides a quick reference guide to the Fortran 90/95 intrinsic functions and subroutines.

Procedures marked with ‘*’ are non-generic versions of other intrinsics. Procedures marked with ‘E’ are elemental.

Procedures marked with ‘I’ are inquiry functions; these query characteristics of a variable other than its value.

Procedures marked with ‘P’ may be supplied as actual procedure arguments; when it is used as a procedure argument all arguments are scalar, no optional arguments are allowed, and it is not generic: if the name is normally generic the procedure argument version is default INTEGER if it begins with the letter I to N, and default REAL otherwise.

Arguments named ‘KIND’ must be initialisation expressions.

Arguments printed in italics (e.g., ‘DIM’) are optional.

Intrinsic Functions

Function Name	Flags	Description
`ABS(A)`	EP	Absolute value.
`ACHAR(I)`	E	Produce character from ASCII value.
`ACOS(X)`	EP	Arccosine.
`ADJUSTL(STRING)`	E	Adjust string to the left by moving leading blanks to the end.
`ADJUSTR(STRING)`	E	Adjust string to the right.
`AIMAG(Z)`	EP	The imaginary part of a complex number.
`AINT(A,KIND )`	EP	Truncate to a whole number.
`ALL(MASK,DIM)`		Reduce `MASK` with the `.AND.` operation.
`ALLOCATED(ARRAY)`	I	Whether an allocatable array is allocated.
`ALOG(X)`	*P	`LOG` function restricted to scalar default real.
`ALOG10(X)`	*P	`LOG10` function restricted to scalar default real.
`AMAX0(A1,A2,A3,...)`	*	`REAL(MAX(A1,A2,A3,...))` with scalar default integer args.
`AMAX1(A1,A2,A3,...)`	*	`MAX` function restricted to scalar default real.
`AMIN0(A1,A2,A3,...)`	*	`REAL(MIN(A1,A2,A3,...))` with scalar default integer args.
`AMIN1(A1,A2,A3,...)`	*	`MIN` function restricted to scalar default integer.
`AMOD(A,P)`	*P	`MOD` function restricted to scalar default real.
`ANINT(A,KIND)`	EP	Round to a whole number.
`ANY(MASK,DIM)`		Reduce `MASK` with the .OR. operation.
`ASIN(X)`	EP	Arcsine.
`ASSOCIATED(POINTER,TARGET)`	I	Whether a pointer is associated with a target.
`ATAN(X)`	EP	Arctangent.
`ATAN2(Y,X)`	EP	Arctangent.
`BIT_SIZE(I)`		Number of bits in an integer type.
`BTEST(I,POS)`	E	Whether a particular bit is 1.
`CABS(A)`	*P	`ABS` function restricted to scalar default complex.
`CCOS(X)`	*P	`COS` function restricted to scalar default complex.
`CEILING(A,KIND)`	E	Smallest integer greater than or equal to `A`.
`CEXP(X)`	*P	`EXP` function restricted to scalar default complex.
`CHAR(I,KIND)`	E	Produce character from native coded character set value.
`CLOG(X)`	*P	`LOG` function restricted to scalar default complex.
`CMPLX(X,Y,KIND)`	E	Convert to complex.
`CONJG(Z)`	EP	Complex conjugate.
`COS(X)`	EP	Cosine.
`COSH(X)`	EP	Hyperbolic cosine.
`COUNT(MASK,DIM)`		Reduce `MASK` by counting `.TRUE.` elements.
`CSHIFT(ARRAY,SHIFT,DIM)`		Circular shift of an array.
`CSIN(X)`	*P	`SIN` function restricted to scalar default complex.
`CSQRT(X)`	*P	`SQRT` function restricted to scalar default complex.
`DABS(A)`	*P	`ABS` function restricted to scalar double precision.
`DACOS(X)`	*P	`ACOS` function restricted to scalar double precision.
`DASIN(X)`	*P	`ASIN` function restricted to scalar double precision.
`DATAN(X)`	*P	`ATAN` function restricted to scalar double precision.
`DATAN2(Y,X)`	*P	`ATAN2` function restricted to scalar double precision.
`DBLE(A)`	E	Convert to double precision.
`DCOS(X)`	*P	`COS` function restricted to scalar double precision.
`DCOSH(X)`	*P	`COSH` function restricted to scalar double precision.
`DDIM(X,Y)`	*P	`DIM` function restricted to scalar double precision.
`DEXP(X)`	*P	`EXP` function restricted to scalar double precision.
`DIGITS(X)`	I	Number of mantissa digits in the model for X.
`DIM(X,Y)`	EP	Non-negative difference, `MAX(0,X-Y)`.
`DINT(A)`	*P	`AINT` function restricted to scalar double precision.
`DLOG(X)`	*P	`LOG` function restricted to scalar double precision.
`DLOG10(X)`	*P	`LOG10` function restricted to scalar double precision.
`DMAX1(A1,A2,A3,...)`	*	`MAX` function restricted to scalar double precision.
`DMIN1(A1,A2,A3,...)`	*	`MIN` function restricted to scalar double precision.
`DMOD(A,P)`	*P	`MOD` function restricted to scalar double precision.
`DNINT(A)`	*P	`ANINT` function restricted to scalar double precision.
`DOT_PRODUCT(VECTOR_A,VECTOR_B)`		Dot product.
`DPROD(X,Y)`	EP	Double precision result of X*Y.
`DSIGN(A,B)`	*P	`SIGN` function restricted to scalar double precision.
`DSIN(X)`	*P	`SIN` function restricted to scalar double precision.
`DSINH(X)`	*P	`SINH` function restricted to scalar double precision.
`DSQRT(X)`	*P	`SQRT` function restricted to scalar double precision.
`DTAN(X)`	*P	`TAN` function restricted to scalar double precision.
`DTANH(X)`	*P	`TANH` function restricted to scalar double precision.
`EOSHIFT(ARRAY,SHIFT,BOUNDARY,DIM)`		End-off array shift.
`EPSILON(X)`	I	Number almost neglible compared to 1.
`EXP(X)`	EP	Exponential (e^X).
`EXPONENT(X)`	E	The exponent part of a floating-point number.
`FLOAT(A)`	*	`REAL` function restricted to scalar default integer.
`FLOOR(A,KIND)`	E	Largest integer less than or equal to `A`.
`FRACTION(X)`	E	The mantissa of a floating-point number.
`HUGE(X)`	I	The largest number in the model for a real type.
`IABS(A)`	*P	`ABS` function restricted to scalar default integer.
`IACHAR(C)`	E	ASCII value for a character.
`IAND(I,J)`	E	Bitwise and.
`IBCLR(I,POS)`	E	Clear specified bit.
`IBITS(I,POS,LEN)`	E	Extract a group of bits.
`IBSET(I,POS)`	E	Set a bit.
`ICHAR(C)`	E	Native coded character set value for a character.
`IDIM(X,Y)`	*P	`DIM` function restricted to scalar default integer.
`IDINT(A)`	*	`INT` function restricted to scalar double precision.
`IDNINT(A)`	*P	`NINT` function restricted to scalar double precision.
`IEOR(I,J)`	E	Bitwise exclusive or.
`IFIX(A)`	*	`INT` function restricted to scalar default real.
`INDEX(STRING,SUBSTRING,BACK)`	EP	Search for substring.
`INT(A,KIND)`	E	Convert to integer.
`IOR(I,J)`	E	Bitwise inclusive or.
`ISHFT(I,SHIFT)`	E	Shift bits.
`ISHFTC(I,SHIFT,SIZE)`	E	Shift bits circularly.
`ISIGN(A,B)`	*P	`SIGN` function restricted to scalar default integer.
`KIND(X)`	I	Kind type parameter of `X`.
`LBOUND(ARRAY,DIM)`	I	Lower bound(s) of an array.
`LEN(STRING)`	IP	Length of a character string.
`LEN_TRIM(STRING)`	E	Length of a character string ignoring trailing blanks.
`LGE(STRING_A,STRING_B)`	E	Comparison (`>=`) using ASCII collating sequence.
`LGT(STRING_A,STRING_B)`	E	Comparison (`>`) using ASCII collating sequence.
`LLE(STRING_A,STRING_B)`	E	Comparison (`<=`) using ASCII collating sequence.
`LLT(STRING_A,STRING_B)`	E	Comparison (`<`) using ASCII collating sequence.
`LOG(X)`	EP	Natural logarithm.
`LOG10(X)`	EP	Common logarithm.
`LOGICAL(L,KIND)`	E	Convert to a specific logical kind.
`MATMUL(MATRIX_A,MATRIX_B)`		Matrix multiplication.
`MAX(A1,A2,A3,...)`	E	Maximum value.
`MAX0(A1,A2,A3,...)`	*	`MAX` function restricted to scalar default integer.
`MAX1(A1,A2,A3,...)`	*	`INT(MAX(A1,A2,A3,...))` with scalar default real args.
`MAXEXPONENT(X)`	I	Maximum model exponent value for `X`.
`MAXLOC(ARRAY,MASK)`		Position of maximum value in an array.
`MAXLOC(ARRAY,DIM,MASK)`		Dimensional reduction of maximum value positions.
`MAXVAL(ARRAY,MASK)`		Reduce a (masked) array with the `MAX` intrinsic.
`MAXVAL(ARRAY,DIM,MASK)`		Dimensional reduction by the `MAX` intrinsic.
`MERGE(TSOURCE,FSOURCE,MASK)`	E	Choose value depending on logical value.
`MIN(A1,A2,A3,...)`	E	Minimum value.
`MIN0(A1,A2,A3,...)`	*	`MIN` function restricted to scalar default integer.
`MIN1(A1,A2,A3,...)`	*	`INT(MIN(A1,A2,A3,...))` with scalar default real args.
`MINEXPONENT(X)`	I	Minimum model exponent value for `X`.
`MINLOC(ARRAY,MASK)`		Position of minimum value in an array.
`MINLOC(ARRAY,DIM,MASK)`		Dimensional reduction of minimum value positions.
`MINVAL(ARRAY,MASK)`		Reduce a (masked) array with the `MIN` intrinsic.
`MINVAL(ARRAY,DIM,MASK)`		Dimensional reduction by the `MIN` intrinsic.
`MOD(A,P)`	EP	Remainder; sign(result) = sign(`A`).
`MODULO(A,P)`	E	Modulo; sign(result) = sign(`P`).
`NEAREST(X,S)`	E	Nearest machine-representable number.
`NINT(A,KIND)`	EP	Round and convert to integer.
`NOT(I)`	E	Bitwise complement.
`NULL(MOLD)`		Null (disassociated) pointer.
`PACK(ARRAY,MASK,VECTOR)`		Pack an array into a vector.
`PRECISION(X)`	I	Decimal model precision for `X`.
`PRESENT(A)`	I	Whether an optional argument is present.
`PRODUCT(ARRAY,MASK)`		Reduce a (masked) array by multiplication.
`PRODUCT(ARRAY,DIM,MASK)`		Dimensional reduction by multiplication.
`RADIX(X)`	I	Model radix for `X`.
`RANGE(X)`	I	Decimal model exponent range for `X`.
`REAL(A,KIND)`	E	Convert to real.
`REPEAT(STRING,NCOPIES)`		Concatenate a string with itself.
`RESHAPE(SOURCE,SHAPE,PAD,ORDER)`		Reshape an array.
`RRSPACING(X)`	E	Reciprocal relative model spacing near `X`.
`SCALE(X,I)`	E	`XRADIX(X)*I`.
`SCAN(STRING,SET,BACK)`	E	Look for characters in a set.
`SELECTED_INT_KIND(R)`		Integer kind with at least `R` decimal digits.
`SELECTED_REAL_KIND(P,R)`		Real kind with at least `P` decimal precision and/or
		at least `R` decimal exponent range.
`SET_EXPONENT(X,I)`	E	`XRADIX(X)*(I-EXPONENT(X))`.
`SHAPE(SOURCE)`	I	Shape of an array.
`SIGN(A,B)`	EP	`A` with the sign of `B`.
`SIN(X)`	EP	Sine.
`SINH(X)`	EP	Hyperbolic sine.
`SIZE(ARRAY,DIM)`	I	Size of an array or dimension.
`SNGL(A)`	*	`REAL` function restricted to scalar double precision.
`SPACING(X)`	E	Spacing of model numbers near `X`.
`SPREAD(SOURCE,DIM,NCOPIES)`		Replicate an array in a given dimension by copying.
`SQRT(X)`	EP	Square root.
`SUM(ARRAY,MASK)`		Reduce a (masked) array by addition.
`SUM(ARRAY,DIM,MASK)`		Dimensional reduction of a (masked) array by addition.
`TAN(X)`	EP	Tangent.
`TANH(X)`	EP	Hyperbolic tangent.
`TINY(X)`	I	Smallest model number for the kind of `X`.
`TRANSFER(SOURCE,MOLD,SIZE)`		Copy internal representation.
`TRANSPOSE(MATRIX)`		Transpose an array.
`TRIM(STRING)`		Character string with trailing blanks removed.
`UBOUND(ARRAY,DIM)`	I	Upper bound(s) of an array.
`UNPACK(VECTOR,MASK,FIELD)`		Unpack a vector into an array.
`VERIFY(STRING,SET,BACK)`	E	Look for characters not in set.

Intrinsic Subroutines

Subroutine Name	Flags	Description
`CPU_TIME(TIME)`		CPU execution time.
`DATE_AND_TIME(DATE,TIME,ZONE,VALUES)`		Date and time information.
`MVBITS(FROM,FROMPOS,LEN,TO,TOPOS)`	E	Move or copy bitfield.
`RANDOM_NUMBER(HARVEST)`		Return pseudo-random number(s).
`RANDOM_SEED(SIZE,PUT,GET)`		Control pseudo-random number generator.
`SYSTEM_CLOCK(COUNT,COUNT_RATE,COUNT_MAX)`		Real-time clock information.