[Kstars-devel] branches/KDE/3.5/kdeedu/kstars/kstars

[Jason Harris]

SVN commit 442973 by harris:

Fixing Bug #109788 (Rounding error when computing arcmin/arcsec for a 
dms angle)

The issue manifests itself when converting a double value with all 
zeroes after the decimal point, to an int.  e.g.:

  double d = 10.000000000;
  int i = int(d);  // i == 9 !! >:(

I tried several ways of massaging the code, but in the end, this is 
the only thing I could get to work:

  double d = 10.000000000;
  int i = int( float(d) );  // i == 10 !! :D
  
So, it works, but maybe it's a kludge and maybe someone knows a better 
way.

Will port to trunk.

CCMAIL: kstars-devel at kde.org
BUG: 109788



 M  +6 -6      dms.cpp  


--- branches/KDE/3.5/kdeedu/kstars/kstars/dms.cpp #442972:442973
@@ -166,7 +166,7 @@
 }
 
 const int dms::arcmin( void ) const {
-	int am = int( 60.0*( fabs(D) - abs( degree() ) ) );
+	int am = int( float( 60.0*( fabs(D) - abs( degree() ) ) ) );
 	if ( D<0.0 && D>-1.0 ) { //angle less than zero, but greater than -1.0
 		am = -1*am; //make minute negative
 	}
@@ -174,7 +174,7 @@
 }
 
 const int dms::arcsec( void ) const {
-	int as = int( 60.0*( 60.0*( fabs(D) - abs( degree() ) ) - abs( arcmin() ) ) );
+	int as = int( float( 60.0*( 60.0*( fabs(D) - abs( degree() ) ) - abs( arcmin() ) ) ) );
 	//If the angle is slightly less than 0.0, give ArcSec a neg. sgn.
 	if ( degree()==0 && arcmin()==0 && D<0.0 ) {
 		as = -1*as;
@@ -183,7 +183,7 @@
 }
 
 const int dms::marcsec( void ) const {
-	int as = int( 1000.0*(60.0*( 60.0*( fabs(D) - abs( degree() ) ) - abs( arcmin() ) ) - abs( arcsec() ) ) );
+	int as = int( float( 1000.0*(60.0*( 60.0*( fabs(D) - abs( degree() ) ) - abs( arcmin() ) ) - abs( arcsec() ) ) ) );
 	//If the angle is slightly less than 0.0, give ArcSec a neg. sgn.
 	if ( degree()==0 && arcmin()==0 && arcsec()== 0 && D<0.0 ) {
 		as = -1*as;
@@ -192,7 +192,7 @@
 }
 
 const int dms::minute( void ) const {
-	int hm = int( 60.0*( fabs( Hours() ) - abs( hour() ) ) );
+	int hm = int( float( 60.0*( fabs( Hours() ) - abs( hour() ) ) ) );
 	if ( Hours()<0.0 && Hours()>-1.0 ) { //angle less than zero, but greater than -1.0
 		hm = -1*hm; //make minute negative
 	}
@@ -200,7 +200,7 @@
 }
 
 const int dms::second( void ) const {
-	int hs = int( 60.0*( 60.0*( fabs( Hours() ) - abs( hour() ) ) - abs( minute() ) ) );
+	int hs = int( float( 60.0*( 60.0*( fabs( Hours() ) - abs( hour() ) ) - abs( minute() ) ) ) );
 	if ( hour()==0 && minute()==0 && Hours()<0.0 ) {
 		hs = -1*hs;
 	}
@@ -208,7 +208,7 @@
 }
 
 const int dms::msecond( void ) const {
-	int hs = int( 1000.0*(60.0*( 60.0*( fabs( Hours() ) - abs( hour() ) ) - abs( minute() ) ) - abs( second() ) ) );
+	int hs = int( float( 1000.0*(60.0*( 60.0*( fabs( Hours() ) - abs( hour() ) ) - abs( minute() ) ) - abs( second() ) ) ) );
 	if ( hour()==0 && minute()==0 && second()==0 && Hours()<0.0 ) {
 		hs = -1*hs;
 	}