Ipomoea alba ?

Ipomoea alba L., Sp. Pl. 1: 161 161 1753. ?


Fwd: Ipomoea id : 6 posts by 1 author. Attachments (1)
Photo taken 27 dec
Is the habitat coastal or estuarine? Size of flower 15 cm?
Central Bangladesh, Flower is big basically the corolla when opened. largest size I  flower I ever seen 
This can be Ipomoea violacea
Most probably Ipomoea alba.